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<rss version="2.0"><channel><title>SoftXML | C Tutorials</title><link>http://www.softxml.com/rss/tutorials/c.xml</link><description>Tutorials</description><pubDate>Sun, 11 Jan 2009 14:27:50 EST</pubDate><language>en-us</language><image><title>SoftXML | C Tutorials</title><url>http://www.softxml.com/images/rsscategory.gif</url><link>http://www.softxml.com/rss/tutorials/c.xml</link><width>80</width><height>73</height></image><item><title>Introducing the Microsoft .NET Framework</title><link>http://www.softxml.com/LearnTutorial.asp?id=48469094490&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt; .NET (dot-net) is the name Microsoft gives to its general vision of

the future of computing, the view being of a world in which many

applications run in a distributed manner across the Internet. We can

identify a number of different motivations driving this vision. &lt;/p&gt;

	

&lt;p&gt; Firstly, distributed computing is rather like object oriented

programming, in that it encourages specialised code to be collected in

one place, rather than copied redundantly in lots of places. There are

thus potential efficiency gains to be made in moving to the distributed

model. &lt;/p&gt;

	

&lt;p&gt; Secondly, by collecting specialised code in one place and opening

up a generally accessible interface to it, different types of machines

(phones, handhelds, desktops, etc.) can all be supported with the same

code. Hence Microsoft's 'run-anywhere' aspiration. &lt;/p&gt;

	

&lt;p&gt; Thirdly, by controlling real-time access to some of the distributed

nodes (especially those concerning authentication), companies like

Microsoft can control more easily the running of its applications. It

moves applications further into the area of 'services provided' rather

than 'objects owned'. &lt;/p&gt;

	

&lt;p&gt; Interestingly, in taking on the .NET vision, Microsoft seems to

have given up some of its proprietary tendencies (whereby all the

technology it touched was warped towards its Windows operating system).

Because it sees its future as providing software services in

distributed applications, the .NET framework has been written so that

applications on other platforms will be able to access these services.

For example, .NET has been built upon open standard technologies like

XML and SOAP. &lt;/p&gt;	

	

&lt;p&gt; At the development end of the .NET vision is the .NET Framework.

This contains the Common Language Runtime, the .NET Framework Classes,

and higher-level features like ASP.NET (the next generation of Active

Server Pages technologies) and WinForms (for developing desktop

applications). &lt;/p&gt;

	

&lt;p&gt; The Common Language Runtime (CLR) manages the execution of code

compiled for the .NET platform. The CLR has two interesting features.

Firstly, its specification has been opened up so that it can be ported

to non-Windows platforms. Secondly, any number of different languages

can be used to manipulate the .NET framework classes, and the CLR will

support them. This has led one commentator to claim that under .NET the

language one uses is a 'lifestyle choice'.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=48469094490&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Getting Started</title><link>http://www.softxml.com/LearnTutorial.asp?id=23786982724&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	Let's begin in the traditional way, by looking at the code of a Hello World 

	program (note that the tabulation and line numbers are included just for the 

	sake of readability).

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;using System;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public class HelloWorld&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													public static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													// This is a single line comment&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													/* This is a

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													multiple

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													line comment */&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine("Hello World! From Softsteel Solutions");&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	The first thing to note about C# is that it is case-sensitive. You will 

	therefore get compiler errors if, for instance, you write 'console' rather than 

	'Console'.

&lt;/p&gt;

&lt;p&gt;

	The second thing to note is that every statement finishes with a semicolon (;) 

	or else takes a code block within curly braces.

&lt;/p&gt;

&lt;p&gt;

	As C# is an object-oriented language, C# programs must be placed in classes, 

	but if you are new to object orientation we suggest that you first read some 

	introductory material). Line 2 above declares the class to be named 

	'HelloWorld'.

&lt;/p&gt;

&lt;p&gt;

	Line 1 of the code declares we are using the System namespace. The point of 

	this declaration is mostly to save ourselves time typing. Because the 'Console' 

	object used in line 10 of the code actually belongs to the 'System' namespace, 

	its fully qualified name is 'System.Console'. However, because in line 1 we 

	declare that the code is using the System namespace, we can then leave off the 

	'System.' part of its name within the code.

&lt;/p&gt;

&lt;p&gt;

	When compiled and run, the program above will automatically run the 'Main' 

	method declared and begun in line 4. Note again C#'s case-sensitivity - the 

	method is 'Main' rather than 'main'.

&lt;/p&gt;

&lt;p&gt;

	Lines 6-9 of the program are ignored by the compiler, being comments entered by 

	the programmer for his own benefit. Line 6 shows a single line comment, in 

	which everything on the line after the two forward slashes is ignored by the 

	compiler. Lines 7-9 demonstrate a multi-line comment, in which everything 

	between the opening /* and closing */ is ignored, even when it spans multiple 

	lines.

&lt;/p&gt;

&lt;p&gt;

	The statement on line 10 calls the 'WriteLine' method of the Console class in 

	the System namespace. It should be obvious how this works in the given example 

	- it just prints out the given string to the 'Console' (on PC machines this 

	will be a DOS prompt).

&lt;/p&gt;

&lt;p&gt;

	In order to run it, the program above must first be saved in a file. Unlike in 

	Java, the name of the class and the name of the file in which it is saved do 

	not need to match up, although it does make things easier if you use this 

	convention. In addition, you are free to choose any extension for the file, but 

	it is usual to use the extension '.cs'.

&lt;/p&gt;

&lt;p&gt;

	Suppose that you have saved the file as 'HelloWorld.cs'. Then to compile the 

	program from a command line, you would use the command

&lt;/p&gt;

&lt;blockquote&gt;csc HelloWorld.cs&lt;/blockquote&gt;

&lt;p&gt;

	(for Visual Studio .</description><guid>http://www.softxml.com/LearnTutorial.asp?id=23786982724&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Variable Types,Reference Types and Value Types</title><link>http://www.softxml.com/LearnTutorial.asp?id=42301366613&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	It is possible in C# to define your own value types by declaring enumerations 

	or structs. These user-defined types are mostly treated in exactly the same way 

	as C#'s predefined value types, although compilers are optimised for the 

	latter. The following table lists, and gives information about, the predefined 

	value types. Because in C# all of the apparently fundamental value types are in 

	fact built up from the (actually fundamental) object type, the list also 

	indicates which System types in the .Net framework correspond to these 

	pre-defined types.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="1" cellpadding="3" cellspacing="0" width="90%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;C# Type&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;.Net Framework (System) type&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Signed?&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Bytes Occupied&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Possible Values&lt;/b&gt;&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;sbyte&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Sbyte&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;1&lt;/td&gt;

			&lt;td class="csharp"&gt;-128 to 127&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;short&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Int16&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;2&lt;/td&gt;

			&lt;td class="csharp"&gt;-32768 to 32767&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;int&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Int32&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;4&lt;/td&gt;

			&lt;td class="csharp"&gt;-2147483648 to 2147483647&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;long&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Int64&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;8&lt;/td&gt;

			&lt;td class="csharp"&gt;-9223372036854775808 to 9223372036854775807&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;byte&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Byte&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

			&lt;td class="csharp"&gt;1&lt;/td&gt;

			&lt;td class="csharp"&gt;0 to 255&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;ushort&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Uint16&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

			&lt;td class="csharp"&gt;2&lt;/td&gt;

			&lt;td class="csharp"&gt;0 to 65535&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;uint&lt;/td&gt;

			&lt;td class="csharp"&gt;System.UInt32&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

			&lt;td class="csharp"&gt;4&lt;/td&gt;

			&lt;td class="csharp"&gt;0 to 4294967295&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;ulong&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Uint64&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

			&lt;td class="csharp"&gt;8&lt;/td&gt;

			&lt;td class="csharp"&gt;0 to 18446744073709551615&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;float&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Single&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;4&lt;/td&gt;

			&lt;td class="csharp"&gt;Approximately ±1.5 x 10&lt;sup&gt;-45 &lt;/sup&gt;to ±3.4 x 10&lt;sup&gt;38 &lt;/sup&gt;with 

				7 significant figures&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;double&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Double&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;8&lt;/td&gt;

			&lt;td class="csharp"&gt;Approximately ±5.0 x 10&lt;sup&gt;-324 &lt;/sup&gt;to ±1.7 x 10&lt;sup&gt;308 &lt;/sup&gt;

				with 15 or 16 significant figures&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;decimal&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Decimal&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

			&lt;td class="csharp"&gt;12&lt;/td&gt;

			&lt;td class="csharp"&gt;Approximately ±1.0 x 10&lt;sup&gt;-28 &lt;/sup&gt;to ±7.9 x 10&lt;sup&gt;28 &lt;/sup&gt;with 

				28 or 29 significant figures&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;char&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Char&lt;/td&gt;

			&lt;td class="csharp"&gt;N/A&lt;/td&gt;

			&lt;td class="csharp"&gt;2&lt;/td&gt;

			&lt;td class="csharp"&gt;Any Unicode character (16 bit)&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;bool&lt;/td&gt;

			&lt;td class="csharp"&gt;System.Boolean&lt;/td&gt;

			&lt;td class="csharp"&gt;N/A&lt;/td&gt;

			&lt;td class="csharp"&gt;1 / 2&lt;/td&gt;

			&lt;td class="csharp"&gt;true or false&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;p&gt;

	In the following lines of code, two variables are declared and set with integer 

	values.

&lt;/p&gt;

&lt;blockquote&gt; int x = 10;&lt;br&gt;

	int y = x;&lt;br&gt;

	y = 20; // after this statement x holds value 10 and y holds value 20&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="2"&gt;Reference Types&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	The pre-defined reference types are object and string, where object - as we 

	have mentioned above - is the ultimate base class of all other types. New 

	reference types can be defined using 'class', 'interface', and 'delegate' 

	declarations.

&lt;/p&gt;

&lt;p&gt;

	Reference types actually hold the value of a memory address occupied by the 

	object they reference. Consider the following piece of code, in which two 

	variables are given a reference to the same object (for the sake of the 

	example, this object is taken to contain the numeric property 'myValue').

&lt;/p&gt;

&lt;blockquote&gt; object x = new object();&lt;br&gt;

	x.myValue = 10;&lt;br&gt;

	object y = x;&lt;br&gt;

	y.myValue = 20; // after this statement both x.myValue and y.myValue equal 20&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	This code illustrates how changing a property of an object using a particular 

	reference to it is reflected in all other references to it. Note, however, that 

	although strings are reference types, they work rather more like value types. 

	When one string is set to the value of another, eg

&lt;/p&gt;

&lt;blockquote&gt; string s1 = "hello";&lt;br&gt;

	string s2 = s1;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Then s2 does at this point reference the same string object as s1. However, 

	when the value of s1 is changed, for instance with

&lt;/p&gt;

&lt;blockquote&gt; s1 = "goodbye";

	&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	what happens is that a new string object is created for s1 to point to. Hence, 

	following this piece of code, s1 equals "goodbye", whereas s2 still equals 

	"hello".

&lt;/p&gt;

&lt;p&gt;

	The reason for this behaviour is that string objects are 'immutable'. That is, 

	the properties of these objects can't themselves change. So in order to change 

	what a string variable references, a new string object must be created.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="3"&gt;Escape Sequences and Verbatim Strings&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	When declaring a string variable, certain characters can't, for various 

	reasons, be included in the usual way. C# supports two different solutions to 

	this problem.

&lt;/p&gt;

&lt;p&gt;

	The first approach is to use 'escape sequences'. For example, suppose that we 

	want to set variable a to the value:

&lt;/p&gt;

&lt;blockquote&gt; "Hello World&lt;br&gt;

	How are you"&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	We could declare this using the following command, which contains escape 

	sequences for the quotation marks and the line break.

&lt;/p&gt;

&lt;blockquote&gt; string a = "\"Hello World\nHow are you\"";&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	The following table gives a list of the escape sequences for the characters 

	that can be escaped in this way:

&lt;/p&gt;

&lt;table align="center" border="1" cellpadding="3" cellspacing="0" width="90%" ID="Table2"&gt;

	&lt;tbody&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Character&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Escape Sequence&lt;/b&gt;&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;'&lt;/td&gt;

			&lt;td class="csharp"&gt;\'&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;"&lt;/td&gt;

			&lt;td class="csharp"&gt;\"&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;\&lt;/td&gt;

			&lt;td class="csharp"&gt;\\&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Alert&lt;/td&gt;

			&lt;td class="csharp"&gt;\a&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Backspace&lt;/td&gt;

			&lt;td class="csharp"&gt;\b&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Form feed&lt;/td&gt;

			&lt;td class="csharp"&gt;\f&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;New Line&lt;/td&gt;

			&lt;td class="csharp"&gt;\n&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Carriage Return&lt;/td&gt;

			&lt;td class="csharp"&gt;\r&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Horizontal Tab&lt;/td&gt;

			&lt;td class="csharp"&gt;\t&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Vertical Tab&lt;/td&gt;

			&lt;td class="csharp"&gt;\v&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;A unicode character specified by its number e.g. \u200

			&lt;/td&gt;

			&lt;td class="csharp"&gt;\u&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;A unicode character specified by its hexidecimal code e.g. \xc8&lt;/td&gt;

			&lt;td class="csharp"&gt;\x&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;null&lt;/td&gt;

			&lt;td class="csharp"&gt;\0 (zero)&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;p&gt;

	The second approach is to use 'verbatim string' literals. These are defined by 

	enclosing the required string in the characters @" and ". To illustrate this, 

	to set the variable 'path' to the following value:

&lt;/p&gt;

&lt;blockquote&gt; C:\My Documents\&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	we could either escape the back-slash characters

&lt;/p&gt;

&lt;blockquote&gt; string path = "C:\\My Documents\\"&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	or use a verbatim string thus:

&lt;/p&gt;

&lt;blockquote&gt; string path = @"C:\MyDocuments\"&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Usefully, strings written using the verbatim string syntax can span multiple 

	lines, and whitespace is preserved. The only character that needs escaping is 

	the double-quote character, the escape sequence for which is two double-quotes 

	together. For instance, suppose that you want to set the variable 'text' to the 

	following value:

&lt;/p&gt;

&lt;blockquote&gt; the word "big" contains three letters.&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Using the verbatim string syntax, the command would look like this:

&lt;/p&gt;

&lt;blockquote&gt; string text = @"the word ""big"" contains three letters."&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="4"&gt;Boxing&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	C# allows you convert any value type to a corresponding reference type, and to 

	convert the resultant 'boxed' type back again. The following piece of code 

	demonstrates boxing.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=42301366613&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Variable Types, Pointers</title><link>http://www.softxml.com/LearnTutorial.asp?id=12237437383&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	This lesson gives a brief overview of pointers and their use in C#. It only 

	scratches the surface of a complicated topic, however, so if you are new to 

	pointers it is recommended that you do further reading before using them in 

	your code. Luckily, pointers are only really needed in C# where execution speed 

	is highly important.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="1"&gt;Pointer Notation&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	A pointer is a variable that holds the memory address of another type. In C#, 

	pointers can only be declared to hold the memory addresses of value types 

	(except in the case of arrays - see below).

&lt;/p&gt;

&lt;p&gt;

	Pointers are declared implicitly, using the 'dereferencer' symbol *, as in the 

	following example:

&lt;/p&gt;

&lt;blockquote&gt; int *p;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	[Note that some coders place the dereferencer symbol immediately after the type 

	name, eg.

&lt;/p&gt;

&lt;blockquote&gt; int* p;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	This variation appears to work just as well as the previous one.]

&lt;/p&gt;

&lt;p&gt;

	This declaration sets up a pointer 'p', which will point to the initial memory 

	address of an integer (stored in four bytes).

&lt;/p&gt;

&lt;p&gt;

	The combined syntactical element *p ('p' prefixed by the dereferencer symbol 

	'*') is used to refer to the type located at the memory location held by p. 

	Hence given its declaration, *p can appear in integer assignments like the 

	following:

&lt;/p&gt;

&lt;blockquote&gt; *p = 5;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	This code gives the value 5 to the integer that was initialised by the 

	declaration. It is important, however, not to confuse such an assignment with 

	one in which the derefencer symbol is absent, e.g.

&lt;/p&gt;

&lt;blockquote&gt; p = 5;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	The effect of this assignment is to change the memory location held by p. It 

	doesn't change the value of the integer initialised by the original 

	declaration; it just means that p no longer points to that integer. In fact, p 

	will now point to the start of the four bytes present at memory location 5.

&lt;/p&gt;

&lt;p&gt;

	Another important symbol for using pointers is the operator &amp;amp;, which in 

	this context returns the memory address of the variable it prefixes. To give an 

	example of this symbol, the following code sets up p to point to integer i's 

	memory location:

&lt;/p&gt;

&lt;blockquote&gt; int i = 5;&lt;br&gt;

	int *p;&lt;br&gt;

	p = &amp;amp;i;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Given the above, the code

&lt;/p&gt;

&lt;blockquote&gt; *p = 10;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	changes the value of i to 10, since '*p' can be read as 'the integer located at 

	the memory value held by p'.

&lt;/p&gt;

&lt;p&gt;

	There is another important piece of notation for pointers. Pointers can be 

	declared for structs (see &lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson11.html#5"&gt;

		lesson 11&lt;/a&gt;), as in the following example (which uses the 'Coords' struct 

	defined further below):

&lt;/p&gt;

&lt;blockquote&gt; Coords x = new Coords();&lt;br&gt;

	Coords *y = &amp;amp;x;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	One can then use the declared pointer y to access a public field of x (say z). 

	This would be done using either the expression

&lt;/p&gt;

&lt;blockquote&gt; (*y).z&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	or the equivalent expression, which uses the -&amp;gt; string:

&lt;/p&gt;

&lt;blockquote&gt; y -&amp;gt; z&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="2"&gt;Unsafe Code&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	A major problem with using pointers in C# is that C# operates a background 

	garbage collection process. In freeing up memory, this garbage collection is 

	liable to change the memory location of a current object without warning. So 

	any pointer which previously pointed to that object will no longer do so. Such 

	a scenario leads to two potential problems. Firstly, it could compromise the 

	running of the C# program itself. Secondly, it could affect the integrity of 

	other programs.

&lt;/p&gt;

&lt;p&gt;

	Because of these problems, the use of pointers is restricted to code which is 

	explicitly marked by the programmer as 'unsafe'. Because of the potential for 

	malicious use of unsafe code, programs which contain unsafe code will only run 

	if they have been given full trust.

&lt;/p&gt;

&lt;p&gt;

	To address the problem of garbage collection, one can declare a pointer within 

	a 'fixed' expression. This 'pins' the location of the type pointed to - the 

	memory location of the type therefore remains static, safe from garbage 

	collection. Note that the fixed statement can only be used within the context 

	of unsafe code.

&lt;/p&gt;

&lt;p&gt;

	There is a further quirk to learn. Any value types declared within unsafe code 

	are automatically 'fixed', and will generate compile-time errors if used within 

	fixed expressions. The same is not true of reference types, however (for the 

	difference between value and reference types see &lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson4.html"&gt;

		lesson 4&lt;/a&gt;).

&lt;/p&gt;

&lt;p&gt;

	The following code gives an example of a method marked 'unsafe'. From the 

	previous paragraph it follows that the pointer p cannot be declared within a 

	'fixed' statement on line 9, because p is set up to point to the struct c (a 

	value type) which is declared within the unsafe code

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;using System;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public struct Coords&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													int x;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													int y;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													unsafe public static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Coords c = new Coords();&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Coords *p = &amp;amp;c;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													p-&amp;gt;y = 6;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													(*p).x = 5;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;13.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;14.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(c.y);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;15.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(c.x);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;16.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;17.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	Compare this with the following code, in which the pointer p on line 8 must be 

	declared within a 'fixed' statment, because it is set up to point to a type 

	which is not declared within the unsafe block of code:

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;using System;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public struct Coords&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													int x;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													int y;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													unsafe public static void notMain(ref Coords c)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													fixed (Coords *p = &amp;amp;c)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													p-&amp;gt;y = 6;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													(*p).x = 5;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;13.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(c.y);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;14.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(c.x);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;15.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;16.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	In the examples given above, 'unsafe' is included as a method modifier. 

	However, it can also be used within a code block, as in the following code 

	fragment:

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;using System;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													unsafe&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Coords c = new Coords();&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													[...]&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="3"&gt;Pointers, Methods and Arrays&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Although we stated above that pointers can only be used with value types, an 

	exception to this involves arrays (some authors state that the same exception 

	applies to strings, but we have never been able to make this work).

&lt;/p&gt;

&lt;p&gt;

	A pointer can be declared in relation to an array, as in the following:

&lt;/p&gt;

&lt;blockquote&gt; int[] a = {4, 5};&lt;br&gt;

	int *b = a;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	What happens in this case is that the memory location held by b is the location 

	of the first type held by a. This first type must, as before, be a value type. 

	The code beneath shows that it is possible to step through the values of an 

	array using a pointer, but explaining this further goes beyond the scope of 

	this tutorial.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table10"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table11"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table12"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;using System;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public class Tester&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													public static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													int[] a = {4, 5};&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													changeVal(a);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(a[0]);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(a[1]);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													public unsafe static void changeVal(int[] a)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;13.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;14.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													fixed (int *b = a)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;15.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;16.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													*b = 5;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;17.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													*(b + 1) = 7;

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;18.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;19.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=12237437383&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Arrays</title><link>http://www.softxml.com/LearnTutorial.asp?id=21565515356&amp;f=c&amp;fo=tutorials</link><description>&lt;h4&gt;&lt;a name="1"&gt;Single-Dimensional Arrays&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	The type of each array declared is given firstly by the type of basic elements 

	it can hold, and secondly by the number of dimensions it has. 

	Single-dimensional arrays have a single dimension (ie, are of rank 1). They are 

	declared using square brackets, eg:

&lt;/p&gt;

&lt;blockquote&gt; int[] i = new int[100];&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	This line of code declares variable i to be an integer array of size 100. It 

	contains space for 100 integer elements, ranging from i[0] to i[99].

&lt;/p&gt;

&lt;p&gt;

	To populate an array one can simply specify values for each element, as in the 

	following code:

&lt;/p&gt;

&lt;blockquote&gt; int[] i = new int[2];

	&lt;br&gt;

	i[0] = 1;&lt;br&gt;

	i[1] = 2;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	One can also run together the array declaration with the assignment of values 

	to elements using

&lt;/p&gt;

&lt;blockquote&gt; int[] i = new int[] {1,2};&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	or the even shorter version of this:

&lt;/p&gt;

&lt;blockquote&gt; int[] i = {1,2};&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	By default, as we have seen, all arrays start with their lower bound as 0 (and 

	we would recommend that you stick with this default). However, using the .NET 

	framework's System.Array class it is possible to create and manipulate arrays 

	with an alternative initial lower bound.

&lt;/p&gt;

&lt;p&gt;

	The (read-only) Length property of an array holds the total number of its 

	elements across all of its dimensions. As single-dimensional arrays have just 

	one dimension, this property will hold the length of the single dimension. For 

	instance, given the definition of array i above, i.Length is 2.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="2"&gt;Rectangular Arrays&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	C# supports two types of multidimensional arrays: rectangular and jagged. A 

	rectangular array is a single array with more than one dimension, with the 

	dimensions' sizes fixed in the array's declaration. The following code creates 

	a 2 by 3 multi-dimensional array:

&lt;/p&gt;

&lt;blockquote&gt; int[,] squareArray = new int[2,3];&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	As with single-dimensional arrays, rectangular arrays can be filled at the time 

	they are declared. For instance, the code

&lt;/p&gt;

&lt;blockquote&gt; int[,] squareArray = {{1, 2, 3}, {4, 5, 6}};&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	creates a 2 by 3 array with the given values. It is, of course, important that 

	the given values do fill out exactly a rectangular array.

&lt;/p&gt;

&lt;p&gt;

	The System.Array class includes a number of methods for determining the size 

	and bounds of arrays. These include the methods GetUpperBound(int i) and 

	GetLowerBound(int i), which return, respectively, the upper and lower 

	subscripts of dimension i of the array (note that i is zero based, so the first 

	array is actually array 0).

&lt;/p&gt;

&lt;p&gt;

	For instance, since the length of the second dimension of squareArray is 3, the 

	expression

&lt;/p&gt;

&lt;blockquote&gt; squareArray.GetLowerBound(1)&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	returns 0, and the expression

&lt;/p&gt;

&lt;blockquote&gt; squareArray.GetUpperBound(1)

	&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	returns 2.

&lt;/p&gt;

&lt;p&gt;

	System.Array also includes the method GetLength(int i), which returns the 

	number of elements in the ith dimension (again, zero based).

&lt;/p&gt;

&lt;p&gt;

	The following piece of code loops through squareArray and writes out the value 

	of its elements (loops are covered in &lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson9.html"&gt;

		lesson 9&lt;/a&gt;).

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;for(int i = 0; i &amp;lt; 

													squareArray.GetLength(0); i++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													for (int j = 0; j &amp;lt; squareArray.GetLength(1); j++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(squareArray[i,j]);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	A foreach loop can also be used to access each of the elements of an array in 

	turn, but using this construction one doesn't have the same control over the 

	order in which the elements are accessed.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="3"&gt;Jagged Arrays&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Using jagged arrays, one can create multidimensional arrays with irregular 

	dimensions. This flexibility derives from the fact that multidimensional arrays 

	are implemented as arrays of arrays. The following piece of code demonstrates 

	how one might declare an array made up of a group of 4 and a group of 6 

	elements:

&lt;/p&gt;

&lt;blockquote&gt; int[][] jag = new int[2][];&lt;br&gt;

	jag[0] = new int [4];&lt;br&gt;

	jag[1] = new int [6];&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	The code reveals that each of jag[0] and jag[1] holds a reference to a 

	single-dimensional int array. To illustrate how one accesses the integer 

	elements: the term jag[0][1] provides access to the second element of the first 

	group.

&lt;/p&gt;

&lt;p&gt;

	To initialise a jagged array whilst assigning values to its elements, one can 

	use code like the following:

&lt;/p&gt;

&lt;blockquote&gt; int[][] jag = new int[][] {new int[] {1, 2, 3, 4}, new int[] {5, 6, 7, 

	8, 9, 10}};&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Be careful using methods like GetLowerBound, GetUpperBound, GetLength, etc. 

	with jagged arrays. Since jagged arrays are constructed out of 

	single-dimensional arrays, they shouldn't be treated as having multiple 

	dimensions in the same way that rectangular arrays do.

&lt;/p&gt;

&lt;p&gt;

	To loop through all the elements of a jagged array one can use code like the 

	following:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;for (int i = 0; i &amp;lt; jag.GetLength(0); i++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													for (int j = 0; j &amp;lt; jag[i].GetLength(0); j++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine(jag[i][j]);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	or

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;for (int i = 0; i &amp;lt; jag.Length; i++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													for (int j = 0; j &amp;lt; jag[i].</description><guid>http://www.softxml.com/LearnTutorial.asp?id=21565515356&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Enumerations</title><link>http://www.softxml.com/LearnTutorial.asp?id=39481950864&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	An enumeration is a special kind of value type limited to a restricted and 

	unchangeable set of numerical values. By default, these numerical values are 

	integers, but they can also be longs, bytes, etc. (any numerical value except 

	char) as will be illustrated below.

&lt;/p&gt;

&lt;p&gt;

	When you define an enumeration you provide literals which are then used as 

	constants for their corresponding values. The following code shows an example 

	of such a definition:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public enum DAYS

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Monday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Tuesday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Wednesday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Thursday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Friday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Saturday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Sunday&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	Note, however, that there are no numerical values specified in the above. 

	Instead, the numerical values are (we think) set up according to the following 

	two rules:

&lt;/p&gt;

&lt;p&gt;

	1. For the first literal: if it is unassigned, set its value to 0.

&lt;/p&gt;

&lt;p&gt;

	2. For any other literal: if it is unassigned, then set its value to one 

	greater than the value of the preceding literal.

&lt;/p&gt;

&lt;p&gt;

	From these two rules, it can be seen that DAYS.Monday will be set to 0, and the 

	values increased until DAYS.Sunday is set to 6. Note also how we are referring 

	to these values - the values specified in an enumeration are static, so we have 

	to refer to them in code using the name of the enumeration: "DAYS.Monday" 

	rather than just "Monday". Furthermore, these values are final - you can't 

	change their runtime value.

&lt;/p&gt;

&lt;p&gt;

	The following code demonstrates how you can override the default setting which 

	makes the default values integers. In this example, the enumeration values are 

	set to bytes.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;enum byteEnum : byte&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													A,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													B&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	You can also override the default numerical values of any and all of the 

	enumeration elements. In the following example, the first literal is set to 

	value 1. The other literals are then set up according to the second rule given 

	above, so DAYS.Sunday will end up equal to 7.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public enum DAYS

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Monday=1,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Tuesday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Wednesday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Thursday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Friday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Saturday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Sunday&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	In the two examples given, the values of each literal has been unique within 

	the enumeration. This is usually how you will want things to be, but in fact 

	the values need not be unique. In the following case, the value of 

	DAYS.Thursday is also set to equal 1. The values assigned to the other literals 

	will follow the rules given previously, so both DAYS.Tuesday and DAYS.Friday 

	will equal 2, etc.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table10"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table11"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table12"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public enum DAYS

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Monday=1,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Tuesday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Wednesday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Thursday=1,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Friday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Saturday,&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Sunday&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	In C# enumerations are type-safe, by which we mean that the compiler will do 

	its best to stop you assigning illicit values to enumeration typed variables. 

	For instance, the following code should not compile:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table13"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table14"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table15"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;int i = DAYS.Monday;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;DAYS d = i;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	In order to get this code to compile, you would have to make explicit casts 

	both ways (even converting from DAYS to int), ie:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table16"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table17"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table18"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;int i = (int)DAYS.Monday;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;DAYS d = (DAYS)i;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	At this point you may be wondering what happens if you cast an int to an 

	enumeration value where that same value is defined for two elements within the 

	enumeration. And the answer is this: one of the elements is given 'primary' 

	status, so it gets picked ahead of the other.

&lt;/p&gt;

&lt;p&gt;

	A useful feature of enumerations is that one can retrieve the literal as a 

	string from the numeric constant with which it is associated. In fact, this is 

	given by the default ToString() method, so the following expression comes out 

	as true:

&lt;/p&gt;

&lt;blockquote&gt; DAYS.Monday.ToString()=="Monday" &lt;/blockquote&gt;

&lt;p&gt;

	The following code prints out both the literal and its constant value for the 

	specified enumeration.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table19"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table20"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table21"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;using System;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;public class EnumTest&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													public enum DAYS: byte

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													public static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Array dayArray = Enum.GetValues(typeof(EnumTest.DAYS));&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													foreach (DAYS day in dayArray)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													Console.WriteLine("Number {1} of EnumTest.DAYS is {0}", day, 

													day.ToString("d"));

												&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;13.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	Since it's not immediately obvious what's going on in the main method here, 

	let's take the time to go through it.

&lt;/p&gt;

&lt;p&gt;

	On line 9 we use the static GetValues method of the Enum class. When you pass 

	this class an enumeration type - in this case, the type corresponding to 

	EnumTest.DAYS - it returns an array of all the values of the elements within 

	that enumeration. Note that the Enum class also has the GetNames method, which 

	returns the literal strings.

&lt;/p&gt;

&lt;p&gt;

	On line 10 we set up a foreach loop, pulling out, into day, each value in the 

	dayArray in turn. Note that this value is of type DAYS.

&lt;/p&gt;

&lt;p&gt;

	On line 11 we use string interpolation as part of the Console.WriteLine method. 

	This method makes use of the String.Format method, so is equivalent to:

&lt;/p&gt;

&lt;blockquote&gt; Console.WriteLine(String.Format("Number {1} of EnumTest.DAYS is {0}", 

	day, day.ToString("d")));&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	And what the String.Format method does is to take 'textual representations' of 

	the objects it is passed as parameters, and slots them into the appropriate 

	places within the 'format string' it is passed. So this line of code is 

	basically equivalent to:

&lt;/p&gt;

&lt;blockquote&gt; Console.WriteLine("Number " + day.ToString("d").ToString() + " of 

	EnumTest.DAYS is " + day.ToString());&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Now, we've already noted that day.ToString() will return a literal string, but 

	what about the method day.ToString("d")? Well, we had a stab at explaining this 

	a while ago, but did very badly. In fact, we just made an error. So hopefully 

	the following will be better.

&lt;/p&gt;

&lt;p&gt;

	The ToString method can take a single IFormatProvider parameter which indicates 

	how the string conversion should be conducted. Values for this parameter can 

	include things like "g", "d", "x", "f", etc. The stated implication of "d", 

	however, is to render in 'Decimal format'. And when we use this on an 

	enumeration member, it provides a string representation of the *numerical 

	value* of the enumeration member.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=39481950864&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Operators</title><link>http://www.softxml.com/LearnTutorial.asp?id=14245929550&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	C# has a number of standard operators, taken from C, C++ and Java. Most of 

	these should be quite familiar to programmers; the less common ones are covered 

	elsewhere.

&lt;/p&gt;

&lt;p&gt;

	The diagram below lists the standard operators. Note that when writing classes 

	it is possible to change the default behaviour of some of these operators (ie 

	to 'overload' the operator), although this should only be done where the 

	resultant semantics makes sense. The diagram indicates which of the operators 

	are overloadable.

&lt;/p&gt;

&lt;table align="center" border="1" cellpadding="3" cellspacing="0" width="90%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Category&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Name&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;&lt;b&gt;Syntax Example&lt;/b&gt;&lt;/td&gt;

			&lt;td class="csharp"&gt;Overloadable?&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Primary&lt;/td&gt;

			&lt;td class="csharp"&gt;Grouping&lt;/td&gt;

			&lt;td class="csharp"&gt;(a+b)&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Member&lt;/td&gt;

			&lt;td class="csharp"&gt;A.B&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Struct pointer member access&lt;/td&gt;

			&lt;td class="csharp"&gt;A-&amp;gt;B&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Method call&lt;/td&gt;

			&lt;td class="csharp"&gt;f(x)&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Post increment&lt;/td&gt;

			&lt;td class="csharp"&gt;c++&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Post decrement&lt;/td&gt;

			&lt;td class="csharp"&gt;c--&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Constructor call&lt;/td&gt;

			&lt;td class="csharp"&gt;c = new Coord();&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Array stack allocation&lt;/td&gt;

			&lt;td class="csharp"&gt;int* c = stackalloc int[10]&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Struct size retrieval&lt;/td&gt;

			&lt;td class="csharp"&gt;sizeof (int)&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Arithmetic check on&lt;/td&gt;

			&lt;td class="csharp"&gt;checked {byte c = (byte) d;}&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Arithmetic check off&lt;/td&gt;

			&lt;td class="csharp"&gt;unchecked {byte c = (byte) d;}&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Unary&lt;/td&gt;

			&lt;td class="csharp"&gt;Positive value&lt;/td&gt;

			&lt;td class="csharp"&gt;+10&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Negative value&lt;/td&gt;

			&lt;td class="csharp"&gt;-10&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Not&lt;/td&gt;

			&lt;td class="csharp"&gt;!(c==d)&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Bitwise complement&lt;/td&gt;

			&lt;td class="csharp"&gt;~(int x)&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Pre increment&lt;/td&gt;

			&lt;td class="csharp"&gt;++c&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Pre decrement&lt;/td&gt;

			&lt;td class="csharp"&gt;--c&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Type cast&lt;/td&gt;

			&lt;td class="csharp"&gt;(myType)c&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Value at address&lt;/td&gt;

			&lt;td class="csharp"&gt;int* c = d;&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Address value of&lt;/td&gt;

			&lt;td class="csharp"&gt;int* c = &amp;amp;d;&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Type operators&lt;/td&gt;

			&lt;td class="csharp"&gt;Type equality / compatibility&lt;/td&gt;

			&lt;td class="csharp"&gt;a is String&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Type retrieval&lt;/td&gt;

			&lt;td class="csharp"&gt;typeof (int)&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Arithmetic&lt;/td&gt;

			&lt;td class="csharp"&gt;Multiplication&lt;/td&gt;

			&lt;td class="csharp"&gt;c*d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Division&lt;/td&gt;

			&lt;td class="csharp"&gt;c/d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Remainder&lt;/td&gt;

			&lt;td class="csharp"&gt;c%d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Addition&lt;/td&gt;

			&lt;td class="csharp"&gt;c+d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Subtraction&lt;/td&gt;

			&lt;td class="csharp"&gt;c-d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Shift bits right&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;gt;&amp;gt;3&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Shift bits left&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;lt;&amp;lt;3&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;Relational and Logical&lt;/td&gt;

			&lt;td class="csharp"&gt;Less than&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;lt;d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Greater than&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;gt;d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Less than or equal to&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;lt;=d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Greater than or equal to&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;gt;=d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Equality&lt;/td&gt;

			&lt;td class="csharp"&gt;c==d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Inequality&lt;/td&gt;

			&lt;td class="csharp"&gt;c!=d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Bitwise and&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;amp;d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Bitwise or&lt;/td&gt;

			&lt;td class="csharp"&gt;c|d&lt;/td&gt;

			&lt;td class="csharp"&gt;Yes&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Logical and&lt;/td&gt;

			&lt;td class="csharp"&gt;c&amp;amp;&amp;amp;d&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Logical or&lt;/td&gt;

			&lt;td class="csharp"&gt;c||d&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

		&lt;tr valign="top"&gt;

			&lt;td class="csharp"&gt;

			&lt;/td&gt;

			&lt;td class="csharp"&gt;Conditional&lt;/td&gt;

			&lt;td class="csharp"&gt;int c=(d&amp;lt;10) ? 5:15&lt;/td&gt;

			&lt;td class="csharp"&gt;No&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="1"&gt;Overloading operators&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	To overload an operator in a class, one defines a method using the 'operator' 

	keyword.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=14245929550&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Flow Control, Loop Statements</title><link>http://www.softxml.com/LearnTutorial.asp?id=25525189476&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	C# provides a number of the common loop statements:

&lt;/p&gt;

&lt;blockquote&gt; while&lt;br&gt;

	do-while&lt;br&gt;

	for&lt;br&gt;

	foreach&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="1"&gt;while loops&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	syntax: while (expression) statement[s]

&lt;/p&gt;

&lt;p&gt;

	A 'while' loop executes a statement, or a block of statements wrapped in curly 

	braces, repeatedly until the condition specified by the boolean expression 

	returns false. For instance, the following code

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;int a = 0;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;while (a &amp;lt; 3)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													System.Console.WriteLine(a);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													a++;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	produces the following output:

&lt;/p&gt;

&lt;blockquote&gt; 0&lt;br&gt;

	1&lt;br&gt;

	2&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="2"&gt;do-while loops&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	syntax: do statement[s] while (expression)

&lt;/p&gt;

&lt;p&gt;

	A 'do-while' loop is just like a 'while' loop except that the condition is 

	evaluated after the block of code specified in the 'do' clause has been run. So 

	even where the condition is initially false, the block runs once. For instance, 

	the following code outputs '4':

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;int a = 4;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;do&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													System.Console.WriteLine(a);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													a++;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;} while (a &amp;lt; 3);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="3"&gt;for loops &lt;/a&gt;

&lt;/h4&gt;

&lt;p&gt;

	syntax: for (statement1; expression; statement2) statement[s]3

&lt;/p&gt;

&lt;p&gt;

	The 'for' clause contains three parts. Statement1 is executed before the loop 

	is entered. The loop which is then executed corresponds to the following 

	'while' loop:

&lt;/p&gt;

&lt;blockquote&gt; statement 1&lt;br&gt;

	while (expression) {statement[s]3; statement2}&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	'For' loops tend to be used when one needs to maintain an iterator value. 

	Usually, as in the following example, the first statement initialises the 

	iterator, the condition evaluates it against an end value, and the second 

	statement changes the iterator value.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;for (int a =0; a&amp;lt;5; a++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;

													System.Console.WriteLine(a);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="4"&gt;foreach loops&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	syntax: foreach (variable1 in variable2) statement[s]

&lt;/p&gt;

&lt;p&gt;

	The 'foreach' loop is used to iterate through the values contained by any 

	object which implements the IEnumerable interface. When a 'foreach' loop runs, 

	the given variable1 is set in turn to each value exposed by the object named by 

	variable2. As we have seen previously, such loops can be used to access array 

	values. So, we could loop through the values of an array in the following way:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table10"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table11"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table12"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;int[] a = new int[]{1,2,3};&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;foreach (int b in a)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="margin: 0px; padding: 0px;"&gt;3.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=25525189476&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Flow Control , Jump and Selection Statements</title><link>http://www.softxml.com/LearnTutorial.asp?id=33129911534&amp;f=c&amp;fo=tutorials</link><description>&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr valign="top"&gt;

			&lt;td&gt;&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr valign="top"&gt;

							&lt;td&gt;&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td&gt;&lt;h4&gt;&lt;a name="1"&gt;Jump Statements&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													The jump statements include

												&lt;/p&gt;

												&lt;blockquote&gt; break&lt;br&gt;

													continue&lt;br&gt;

													goto&lt;br&gt;

													return

													&lt;br&gt;

													throw

													&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													&lt;b&gt;break&lt;/b&gt;

												&lt;/p&gt;

												&lt;p&gt;

													The 'break' statement breaks out of the 'while' and 'for' and the 'switch' 

													statements covered later in this lesson. The following code gives an example - 

													albeit a very inefficient one - of how it could be used. The output of the loop 

													is the numbers from 0 to 4.

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;int 

																									a = 0;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;while 

																									(true)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									System.Console.WriteLine(a);&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									a++;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									if (a == 5)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									break;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													&lt;b&gt;continue&lt;/b&gt;

												&lt;/p&gt;

												&lt;p&gt;

													The 'continue' statement can be placed in any loop structure. When it executes, 

													it moves the program counter immediately to the next iteration of the loop. The 

													following code example uses the 'continue' statement to count the number of 

													values between 1 and 100 inclusive that are not multiples of seven. At the end 

													of the loop the variable y holds the required value.

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;int 

																									y = 0;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;for 

																									(int x=1; x&amp;lt;101; x++)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									if ((x % 7) == 0)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									continue;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									y++;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													&lt;b&gt;goto &lt;/b&gt;

												&lt;/p&gt;

												&lt;p&gt;

													The 'goto' statement is used to make a jump to a particular labelled part of 

													the program code. It is also used in the 'switch' statement described below. We 

													can use a 'goto' statement to construct a loop, as in the following example 

													(but again, this usage is not recommended):

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table10"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table11"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table12"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;int 

																									a = 0;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;start:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;System.Console.WriteLine(a);&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;a++;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;if 

																									(a &amp;lt; 5)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									goto start;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

												&lt;/p&gt;

												&lt;h4&gt;&lt;a name="2"&gt;Selection Statements&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													C# offers two basic types of selection statement:

												&lt;/p&gt;

												&lt;blockquote&gt; if - else&lt;br&gt;

													switch - default&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													&lt;b&gt;if - else&lt;/b&gt;

												&lt;/p&gt;

												&lt;p&gt;

													'If-else' statements are used to run blocks of code conditionally upon a 

													boolean expression evaluating to true. The 'else' clause, present in the 

													following example, is optional.

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table13"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table14"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table15"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;if 

																									(a == 5)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									System.Console.WriteLine("A is 5");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;else&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									System.Console.WriteLine("A is not 5");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													If statements can also be emulated by using the conditional operator. The 

													conditional operator returns one of two values, depending upon the value of a 

													boolean expression. To take a simple example, the line of code

												&lt;/p&gt;

												&lt;blockquote&gt; int i = (myBoolean) ? 1 : 0 ;&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													sets i to 1 if myBoolean is true, and sets i to 0 if myBoolean is false. The 

													'if' statement in the previous code example could therefore be written like 

													this:

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table16"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table17"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table18"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;System.Console.WriteLine( 

																									a==5 ? "A is 5" : "A is not 5");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													&lt;b&gt;switch - default&lt;/b&gt;

												&lt;/p&gt;

												&lt;p&gt;

													'Switch' statements provide a clean way of writing multiple if - else 

													statements. In the following example, the variable whose value is in question 

													is 'a'. If a equals 1, then the output is 'a&amp;gt;0'; if a equals 2, then the 

													output is 'a&amp;gt;1 and a&amp;gt;0'. Otherwise, it is reported that the variable is 

													not set.

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table19"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table20"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table21"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;switch(a)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									case 2:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									Console.WriteLine("a&amp;gt;1 and ");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									goto case 1;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									case 1:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									Console.WriteLine("a&amp;gt;0");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									break;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									default:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									Console.WriteLine("a is not set");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;11.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									break;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;12.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													Each case (where this is taken to include the 'default' case) will either have 

													code specifying a conditional action, or no such code. Where a case does have 

													such code, the code must (unless the case is the last one in the switch 

													statement) end with one of the following statements:

												&lt;/p&gt;

												&lt;blockquote&gt; break;&lt;br&gt;

													goto case k; (where k is one of the cases specified)&lt;br&gt;

													goto default;&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													From the above it can be seen that C# 'switch' statements lack the default 

													'fall through' behaviour found in C++ and Java. However, program control does 

													fall through wherever a case fails to specify any action. The following example 

													illustrates this point; the response "a&amp;gt;0" is given when a is either 1 or 2.

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table22"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table23"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table24"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;switch(a)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									case 1:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									case 2:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									Console.WriteLine("a&amp;gt;0");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									break;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									default:&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									Console.WriteLine("a is not set");&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;

																									break;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=33129911534&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Introducing Classes, Structs and Namespaces</title><link>http://www.softxml.com/LearnTutorial.asp?id=26356526645&amp;f=c&amp;fo=tutorials</link><description>&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr valign="top"&gt;

			&lt;td&gt;&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr valign="top"&gt;

							&lt;td&gt;&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td&gt;&lt;h4&gt;&lt;a name="1"&gt;Classes and Types&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													As we noted previously, one can create new reference types by defining classes. 

													Classes provide 'templates' from which these direct instances are generated. 

													Where we appeal to the relation between a class and its corresponding reference 

													type instances we shall say that a class specifies the type (also that the 

													class specifies the constitutive elements of the type).

												&lt;/p&gt;

												&lt;p&gt;

													Any type is made up of elements, which we term type members. There are two main 

													kinds of type members that a class can specify. Firstly, a class can specify 

													other types - both value and reference. This idea, that types can contain other 

													types, is known within the literature on object orientation as 'containment', 

													or else 'aggregation'. Where a type contains another reference type, we shall 

													call it the containing type of the latter.

												&lt;/p&gt;

												&lt;p&gt;

													The second, main kind of type members that a class can specify are methods, 

													functions designed for reading and manipulating the value and reference types 

													an instance contains.

												&lt;/p&gt;

												&lt;table align="center" cellpadding="10" cellspacing="10" ID="Table4"&gt;

													&lt;tbody&gt;

														&lt;tr valign="bottom"&gt;

															&lt;td align="center"&gt;&lt;img src="http://www.softsteel.co.uk/layout/cLess11a.jpg" alt="a picture illustrating a reference type object"

																	name="" height="150" width="400"&gt;&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;p&gt;

												&lt;/p&gt;

												&lt;h4&gt;&lt;a name="2"&gt;Inheritance&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													Object oriented languages like C# allow inheritance from reference types. If a 

													type inherits from another, it takes on all of its type members. A type can, 

													however, both add to the members it inherits in this way, as well as 

													'overwriting' them. To overwrite a type member - a method, say - the defining 

													class specifies a method with the same name as one that it inherits.

												&lt;/p&gt;

												&lt;p&gt;

													C#'s inheritance model is more similar to Java's than to C++'s. In particular, 

													C# classes inherit always from a single base class (if one is not specified in 

													the declaration, inheritance is from System.Object). At the same time, however, 

													C# classes can inherit from any number of interfaces.

												&lt;/p&gt;

												&lt;p&gt;

												&lt;/p&gt;

												&lt;h4&gt;&lt;a name="3"&gt;Abstract Classes and Interfaces&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													Some classes are not designed to have direct instances. Rather, they are 

													designed simply to be inherited from, by ancestors which may themselves have 

													direct instances (or not). A class is 'abstract' just in case it cannot itself 

													have direct instances.

												&lt;/p&gt;

												&lt;p&gt;

													Classes can be abstract because in a class it is possible to specify a class 

													method without specifying its body. Such methods are themselves termed 

													'abstract'. Where a class contains an abstract method it cannot be 

													instantiated, since it is not specified what should happen were the method to 

													be called.

												&lt;/p&gt;

												&lt;p&gt;

													An 'interface' is a class which has only abstract methods. However, such a 

													class is declared not with the 'class' keyword but the 'interface' keyword. 

													Above we stated that a C# class can only inherit from one 'base' class; but 

													this ignores interfaces. A class can inherit from any number of interfaces.

												&lt;/p&gt;

												&lt;p&gt;

												&lt;/p&gt;

												&lt;h4&gt;&lt;a name="4"&gt;Nested Classes&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													Classes are usually specified independently of each other. But it is possible 

													for one class to be specified within another's specification. In this case, the 

													latter class is termed a nested class.

												&lt;/p&gt;

												&lt;p&gt;

												&lt;/p&gt;

												&lt;h4&gt;&lt;a name="5"&gt;Structs&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													A struct is a user-defined value type. It is declared in a very similar way to 

													a class, except that it can't inherit from any class, nor can any class inherit 

													from it (as mentioned previously, however, all value types do inherit from 

													System.object). The following example shows a partial declaration for a 

													'Coordinate' struct:

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table5"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table6"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table7"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;struct Coordinate&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									public int x;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									public int y;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									public Coordinate(int x, int y)&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									this.x = x;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									this.y = y;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;11.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													Given the above, one could initialise a Coordinate type in a familiar way, 

													using code like:

												&lt;/p&gt;

												&lt;blockquote&gt;Coordinate c = new Coordinate(10, 2);&lt;/blockquote&gt;

												&lt;p&gt;

													Note that if a variable of a struct type is declared without being given an 

													explicit value, eg:

												&lt;/p&gt;

												&lt;blockquote&gt;Coordinate c2 ;&lt;/blockquote&gt;

												&lt;p&gt;

													it does not equate to 'null' (this being the default value for reference types, 

													rather than value types). Instead, the variable is initialised to a state where 

													its fields have their default values. If these fields are basic value types, 

													they will generally be set to zero. If these fields are reference types, they 

													will be set to 'null'.

												&lt;/p&gt;

												&lt;p&gt;

													Because of this default initialisation behaviour, it is an error for a struct 

													to be given a parameterless constructor (eg. one like 'public Coordinate()'). 

													Also, where a struct does have a constructor, you should be sure to make 

													assignments to all of the struct's fields within this constructor.

												&lt;/p&gt;

												&lt;p&gt;

												&lt;/p&gt;

												&lt;h4&gt;&lt;a name="6"&gt;Namespaces&lt;/a&gt;&lt;/h4&gt;

												&lt;p&gt;

													Namespaces can be thought of as collections of classes; they provide unique 

													identifiers for types by placing them in an hierarchical structure.

												&lt;/p&gt;

												&lt;p&gt;

													To illustrate the use of namespaces: suppose that two different C# developers 

													come up with a class called 'bank', one relating to fiscal institutions and the 

													other relating to riversides. In a programming environment containing both 

													classes, there is a need to distinguish one from the other, and this is 

													achieved by placing them within different namespaces. For example, the former 

													class could be placed within the 'fiscal' namespace, say, becoming fiscal.bank, 

													whereas the latter could be placed within the 'river' namespace becoming 

													river.bank. (Note that C# does not include Java's direct link between the 

													namespace hierarchy and the file structure hierarchy).

												&lt;/p&gt;

												&lt;p&gt;

													Most classes depend upon the existence of other classes - for instance, they 

													may specify contained types. It is possible in the specification always to 

													write each class' full namespace, but these are often too long for it to be 

													worthwhile. To take an example at random, the following is the fully qualified 

													name of a class in the .NET framework relating to a particular type of 

													cryptographic algorithm:

												&lt;/p&gt;

												&lt;blockquote&gt; System.Security.Cryptography.AsymmetricAlgorithm&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													This problem is addressed by the use of the 'using' keyword, placed at the very 

													top of the class specification. For instance, in a class specification 

													including the phrase

												&lt;/p&gt;

												&lt;blockquote&gt; using System.Security.Cryptography;&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													one could write refer to the above class simply using its class name

												&lt;/p&gt;

												&lt;blockquote&gt; AsymmetricAlgorithm&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													Alternatively, one could specify an alias for the namespace, eg

												&lt;/p&gt;

												&lt;blockquote&gt; using myAlias = System.Security.Cryptography;&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													and then refer to the class with

												&lt;/p&gt;

												&lt;blockquote&gt; myAlias.AsymmetricAlgorithm&lt;br&gt;

												&lt;/blockquote&gt;

												&lt;p&gt;

													One specifies a namespace for one's own classes using the 'namespace' keyword. 

													For instance, the following code states that the class 'Adder' is in the 

													namespace fred.math.

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table8"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table9"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table10"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;namespace fred&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									namespace math&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									public class Adder&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									// insert code here&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;8.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;9.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;10.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

													Alternatively, and more simply, one write the above as:

												&lt;/p&gt;

												&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table11"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table12"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#ffffff"&gt;

																				&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table13"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;1.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;namespace fred.math&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;2.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;3.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									public class Adder&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;4.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									{&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;5.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									// insert code here&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;6.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;

																									}&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																						&lt;tr valign="top"&gt;

																							&lt;td width="10%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;7.&lt;/p&gt;

																							&lt;/td&gt;

																							&lt;td width="90%"&gt;

																								&lt;p style="margin: 0px; padding: 0px;"&gt;&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																			&lt;/td&gt;

																		&lt;/tr&gt;

																	&lt;/tbody&gt;

																&lt;/table&gt;

															&lt;/td&gt;

														&lt;/tr&gt;

													&lt;/tbody&gt;

												&lt;/table&gt;

												&lt;br&gt;

												&lt;p&gt;

												&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="10"&gt;

											&lt;/td&gt;

											&lt;td width="140"&gt;&lt;table border="0" cellpadding="2" cellspacing="0" width="140" ID="Table14"&gt;

													&lt;tbody&gt;

														&lt;tr&gt;

															&lt;td bgcolor="#00008b"&gt;

																&lt;table border="0" cellpadding="4" cellspacing="0" width="100%" ID="Table15"&gt;

																	&lt;tbody&gt;

																		&lt;tr&gt;

																			&lt;td bgcolor="#cccccc"&gt;&lt;table cellpadding="0" cellspacing="0" ID="Table16"&gt;

																					&lt;tbody&gt;

																						&lt;tr valign="bottom"&gt;

																							&lt;td&gt;&lt;img src="http://www.softsteel.co.uk/images/softsteelarrow.gif" border="0"&gt;&lt;br&gt;

																							&lt;/td&gt;

																							&lt;td&gt;

																								&lt;!--LOCALuplinkAdd=&lt;IMG SRC="/images/softsteelarrow.gif" BORDER="0"&gt;&lt;BR&gt;--&gt;

																								&lt;p class="localLinks"&gt;

																									&lt;a href="http://www.softsteel.co.uk/tutorials/index.html"&gt;all tutorials&lt;/a&gt;

																								&lt;/p&gt;

																							&lt;/td&gt;

																						&lt;/tr&gt;

																					&lt;/tbody&gt;

																				&lt;/table&gt;

																				&lt;h4 align="left"&gt;C# Tutorial&lt;/h4&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/cIndex.html"&gt;the 

																						C# tutorial&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/contents.html"&gt;contents&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson1.html"&gt;1 

																						.NET Framework&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson2.html"&gt;2 

																						C# vs C++/Java&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson3.html"&gt;3 

																						'hello world'&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson4.html"&gt;4 

																						variable types&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson5.html"&gt;5 

																						pointers&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson6.html"&gt;6 

																						arrays&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson7.html"&gt;7 

																						enumerations&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson8.html"&gt;8 

																						operators&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson9.html"&gt;9 

																						loops&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson10.html"&gt;10 

																						jump/selection&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson11.html"&gt;11 

																						classes...&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson12.html"&gt;12 

																						...declaration&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson13.html"&gt;13 

																						methods&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson14.html"&gt;14 

																						polymorphism&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson15.html"&gt;15 

																						constants...&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson16.html"&gt;16 

																						delegates...&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson17.html"&gt;17 

																						exceptions&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson18.html"&gt;18 

																						compiler&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson19.html"&gt;19 

																						documentation&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson20.html"&gt;20 

																						references&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/booksUS.asp"&gt;C# 

																						books (Int)&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/booksUK.asp"&gt;C# 

																						books (UK)&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/patch.html"&gt;patchwork 

																						book&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson21.html"&gt;21 

																						[2.0] generics&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson21.html"&gt;&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson22.html"&gt;22 

																						[2.0] anon. methods&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson22.html"&gt;&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson23.html"&gt;23 

																						[2.0] iterators&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson23.html"&gt;&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson24.html"&gt;24 

																						[2.0] partial...&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson24.html"&gt;&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson25.html"&gt;25 

																						[2.0] nullable...&lt;/a&gt;&lt;/p&gt;

																				&lt;p class="localLinks"&gt;&lt;a href="http://www.softsteel.co.uk/tutorials/cSharp/lesson25.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=26356526645&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Class Declaration</title><link>http://www.softxml.com/LearnTutorial.asp?id=40889103847&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	Class declarations can have up to four different parts, surrounding the 'class' 

	keyword:

&lt;/p&gt;

&lt;blockquote&gt; attributes class-modifiers class class-base class-body&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	The class-body element specifies type members. The following is an example of a 

	very simple class declaration, the class body being the lines following line 1:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													class Shape&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;// 

													class-body&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	We now consider the other parts of a class declaration.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="1"&gt;Attributes&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

Attributes can be posted at the front of a class declaration. These comprise 

user-defined 'meta-data' about the class; information which can be brought out 

at runtime. The example given in the C# language reference is this: one might 

define a 'HelpAttribute' attribute in order to map classes to their 

documentation.

&lt;p&gt;

&lt;/p&gt;

&lt;a name="2"&gt;Class Modifiers&lt;/a&gt; &lt;/p&gt;

&lt;p&gt;

	There are seven different - optional - class modifiers. Four of these - 

	'public', 'internal', 'protected' and 'private' - are used to specify the 

	access levels of the types defined by the classes. The following five different 

	access levels can be specified with these four modifiers:

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;public&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	The 'public' keyword identifies a type as fully accessible to all other types. 

	This is the implicit accessibility of enumeration members and interface 

	members.

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;internal&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	If a class is declared as 'internal', the type it defines is accessible only to 

	types within the same assembly (a self-contained 'unit of packaging' containing 

	code, metadata etc.). This is the default access level of non-nested classes.

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;protected&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	If a class is declared as 'protected', its type is accessible by a containing 

	type and any type that inherits from this containing type. This modifier should 

	only be used for internal classes (ie. classes declared within other classes).

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;protected internal&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	The permissions allowed by this access level are those allowed by the 

	'protected' level plus those allowed by the 'internal' level. The access level 

	is thus more liberal than its parts taken individually. This modifier should 

	only be used for internal classes (ie. classes declared within other classes).

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;private&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	Where a class is declared as 'private', access to the type it defines is 

	limited to a containing type only. This modifier should only be used for 

	internal classes (ie. classes declared within other classes).

&lt;/p&gt;

&lt;p&gt;

	We now turn to the final three class modifiers:

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;new&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	The 'new' keyword can be used for 'nested' classes. A nested class is one that 

	is defined in the body of another class; it is in most ways identical to a 

	class defined in the normal way, but its access level cannot be more liberal 

	than that of the class in which it is defined. A nested class should be 

	declared using the 'new' keyword just in case it has the same name as (and thus 

	overrides) an inherited type.

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;abstract&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	A class declared as 'abstract' cannot itself be instanced - it is designed only 

	to be a base class for inheritance.

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;sealed&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	A class declared as 'sealed' cannot be inherited from.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="3"&gt;Class Base&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	The 'class base' part of the class declaration specifies the name of the class 

	and any classes that it inherits from.

&lt;/p&gt;

&lt;p&gt;

	As we noted previously, classes can inherit from just one base class and any 

	number of interfaces. The classes to be inherited from are named following a 

	colon after the class's own name (with any base class preceding any 

	interfaces).</description><guid>http://www.softxml.com/LearnTutorial.asp?id=40889103847&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Introducing Methods</title><link>http://www.softxml.com/LearnTutorial.asp?id=31089305578&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	Methods are operations associated with types. To provide a type with methods is 

	to give it some useful functionality. Often this functionality is made 

	generally available, so that it can be utilised by other types

&lt;/p&gt;

&lt;p&gt;

	To take a simple example, suppose that we have an 'Arithmetic' class, whose 

	purpose is to provide arithmetic operations. One simple method this class could 

	have is the 'addTwoIntegers' method, whose job is to support the operation of 

	adding two integers. To make use of this functionality, a piece of code would 

	'call' the method by 'passing' it two integers. The method would then 'return' 

	their sum. Such a piece of code might look like this:

&lt;/p&gt;

&lt;blockquote&gt; int sum = Arithmetic.addTwoIntegers(4,7);&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	A method declaration, specified within a class declaration, comprises a 

	method-head and a method-body. The method-head is made up of the following 

	elements (square brackets enclose those which are optional).

&lt;/p&gt;

&lt;blockquote&gt; [attributes] [method-modifiers] return-type method-name ([ 

	formal-parameter-list] )

	&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	In the case of the example method, its method head could look something like 

	this:

&lt;/p&gt;

&lt;blockquote&gt; [Description("a pointless method")] public static int 

	addTwoIntegers(int a, int b)&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="1"&gt;Attributes&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Method attributes work in a similar way to that briefly described for classes. 

	We do not in this tutorial try to cover the different types of attributes that 

	there are.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="2"&gt;Method Modifiers&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	There are ten method modifiers that can be used. Four of these are the access 

	modifiers that can be used in class declarations. These four work analogously 

	to the way they work in class declarations. The others are the following:

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;abstract&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;static&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	The 'static' modifier declares a method to be a class method.

&lt;/p&gt;

&lt;p&gt;

	The methods (as well as the enumerations, properties and variables) specified 

	in a class can be associated either with the class's instances (ie. the 

	reference types it specifies) or with the class itself. These methods are 

	called, respectively, 'instance methods' and 'class methods'. Class methods, 

	declared with the 'static' modifier, can be called even when there exists no 

	current instances of the class.

&lt;/p&gt;

&lt;p&gt;

	There is no equivalent modifier for instance methods, since methods are 

	instance methods just in case their declaration does not include the word 

	'static'.

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;new, virtual, override&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	These modifiers concern the inheritance of methods from super- to sub-classes.

&lt;/p&gt;

&lt;P&gt;

	&lt;b&gt;extern&lt;/b&gt;

&lt;/P&gt;

&lt;p&gt;

	Methods which are given as 'extern' are defined externally, using a language 

	other than C#. We shall not go into the process involved in defining such 

	methods.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="3"&gt;Formal Parameters&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	A method's parameters are the types that get passed to it when the method is 

	called. The list of parameters begins by specifying zero or more 'fixed 

	parameters', and it may finish by specifying a single parameter-array. This 

	latter element - declared using the 'params' keyword - means that it is 

	possible to pass an arbitrary number of types to a single method. An example is 

	given later in the lesson.

&lt;/p&gt;

&lt;p&gt;

	Fixed parameter specifications can have either two or three parts (ignoring 

	attributes). The first, optional modifier can be either 'ref' or 'out'. The 

	second part of the specification specifies the parameter's type, and the third 

	part its name. Examples of these different elements can be seen in the 

	illustrative code in the sections below.

&lt;/p&gt;

&lt;blockquote&gt; [Modifier] parameter-type parameter-identifier&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="4"&gt;Parameter Passing&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	&lt;b&gt;passing by value&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	The parameter modifiers 'ref' and 'out' relate to how the parameter is passed 

	into the method. Where neither of these modifiers is used, the parameter is 

	passed in 'by value'. In this case, when the method is called the value given 

	is copied to the variable specified in the method declaration. The following 

	example illustrates this point; note that the change made to variable b in the 

	body of the 'change' method doesn't result in a change to the variable a used 

	to invoke the method.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													a = 0;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;change(a); 

													// following this method invocation, a equals 0&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static void change(int b)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;b 

													= 5;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	In this example, it was a value type that was passed 'by value'. But reference 

	types can also be passed 'by value'. As we saw previously, the immediate value 

	held by a reference type variable is actually a memory address. So when this 

	variable is passed 'by value', the memory address is copied to the variable 

	specified in the method head. But of course, because the two variables will 

	hold the same memory address, any changes made within the method body to the 

	object located at that memory address will be reflected outside the method 

	(although this doesn't apply for immutable reference types like strings, which 

	act more like value types).

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;passing by reference&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	In C# we can pass variables into methods 'by reference'. Where a variable is 

	passed by reference, the 'ref' modifier must be used both in the method head 

	and the method invocation (illustrated by the next code block).

&lt;/p&gt;

&lt;p&gt;

	Passing by reference is most obviously useful in cases where we want to treat a 

	value type like a reference type. For instance, the method call in the 

	following code does change the value of the variable a passed into the 'change' 

	method.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													a = 0;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;change(ref 

													a); // following this method invocation, a==5&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static void change (ref int b)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;b 

													= 5;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	&lt;b&gt;'output' parameters&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	Where a method parameter is defined (and invoked) using the 'out' modifier, it 

	is passed by reference. The difference between the 'out' and the 'ref' modifier 

	is this: a parameter modified by the 'out' keyword need not be assigned a value 

	before being passed into the method, but must be assigned a value in the 

	method.

&lt;/p&gt;

&lt;p&gt;

	The reason that one might use output parameters is to return multiple values 

	from a method. For instance, in the following code an integer and a boolean is 

	passed to the 'change' method. This method sets the boolean to indicate whether 

	or not the integer is greater than 0, and returns the value of the integer 

	doubled.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;bool 

													b;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													c = change(5, out b);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static int change (int a, out bool b)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;b=false;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;if 

													(a&amp;gt;0)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;b=true;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													(2*a);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;13.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="5"&gt;The params modifier&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	One can pass an arbitrary number of types to a method by declaring a parameter 

	array with the 'params' modifier. Note, though, that it is not necessary to 

	place these additional types into an array before calling the method - they can 

	simply be listed in the method invocation (see the next code block for an 

	example).

&lt;/p&gt;

&lt;p&gt;

	Types passed as 'params' are all passed by value. The following code gives an 

	example of the use of the 'params' modifier; the method called ignores the 

	first type passed to it (a double) and returns the sum of all (an arbitrary 

	number of) the integer values passed to it.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table10"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table11"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table12"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static void Main()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;double 

													a = 1;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													b = 2;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													c = 3;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													d = totalIgnoreFirst(a, b, c);&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static int totalIgnoreFirst(double a, params int[] intArr)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													sum = 0;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;for 

													(int i=0; i &amp;lt; intArr.Length; i++)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;13.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;sum 

													+= intArr[i];&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;14.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													sum;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;15.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="6"&gt;Return Type&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Methods can either return a type or not. A method that doesn't return a type 

	must give its return type as 'void'. A method that does return a type must name 

	the type returned.

&lt;/p&gt;

&lt;p&gt;

	A method will stop and return a value if it reaches a 'return' statement at any 

	point in its execution. The type returned is given at the end of such a return 

	statement; its type must correspond with that specified in the method 

	declaration. The following piece of code illustrates this point.

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table13"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table14"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table15"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													static int exampleMethod()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;int 

													i =0;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;// 

													process i&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													i;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="7"&gt;Method Overloading&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Each method has a signature. This comprises the method's name and its 

	parameters (excepting their names), but not the method's return type. In the 

	following method header, the elements making up the method's signature are 

	emphasised - note also that the 'params' keyword is not included in the 

	signature.

&lt;/p&gt;

&lt;blockquote&gt; public static int &lt;b&gt;myMethod&lt;/b&gt;(&lt;b&gt;int&lt;/b&gt; a, &lt;b&gt;ref double&lt;/b&gt; b, &lt;b&gt;out 

		bool&lt;/b&gt; c, params &lt;b&gt;int[]&lt;/b&gt; d)&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	The importance of the signature is that no class is allowed to contain two 

	methods with the same signature. Since the signature takes in more than the 

	method name, however, it is possible for one class to have methods sharing a 

	name.</description><guid>http://www.softxml.com/LearnTutorial.asp?id=31089305578&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Polymorphism (Inherited Methods)</title><link>http://www.softxml.com/LearnTutorial.asp?id=5327089719&amp;f=c&amp;fo=tutorials</link><description>&lt;p&gt;

	As we have seen previously , classes take on the methods of the classes from 

	which they inherit. In some cases, however, a class may want to 'overwrite' 

	such a method. C# supports two different ways of method overwriting - 'hiding' 

	or 'overriding'. Note that the term 'overwrite' is a term we have devised to 

	cover both hiding and overriding.

&lt;/p&gt;

&lt;p&gt;

	Method overwriting makes use of the following three method-head keywords:

&lt;/p&gt;

&lt;blockquote&gt; new, virtual, override&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	The main difference between hiding and overriding relates to the choice of 

	which method to call where the declared class of a variable is different to the 

	run-time class of the object it references. This point is explained further 

	below.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="1"&gt;Method Overriding&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Suppose that we define a Square class which inherits from a Rectangle class (a 

	square being a special case of a rectangle). Each of these classes also 

	specifies a 'getArea' instance method, returning the area of the given 

	instance.

&lt;/p&gt;

&lt;p&gt;

	For the Square class to 'override' the Rectangle class' getArea method, the 

	Rectangle class' method must have first declared that it is happy to be 

	overridden. One way in which it can do this is with the 'virtual' keyword. So, 

	for instance, the Rectangle class' getArea method might be specified like this:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													virtual double getArea()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													length * width;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	To override this method the Square class would then specify the overriding 

	method with the 'override' keyword. For example:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													override double getArea()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													length * length;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	Note that for one method to override another, the overridden method must not be 

	static, and it must be declared as either 'virtual', 'abstract' or 'override'. 

	Furthermore, the access modifiers for each method must be the same.

&lt;/p&gt;

&lt;p&gt;

	The major implication of the specifications above is that if we construct a new 

	Square instance and then call its 'getArea' method, the method actually called 

	will be the Square instance's getArea method. So, for instance, if we run the 

	following code:

&lt;/p&gt;

&lt;blockquote&gt; Square sq = new Square(5);&lt;br&gt;

	double area = sq.getArea();&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	then the getArea method called on the second line will be the method defined in 

	the Square class.

&lt;/p&gt;

&lt;p&gt;

	There is, however, a more subtle point. To show this, suppose that we declare 

	two variables in the following way:

&lt;/p&gt;

&lt;blockquote&gt; Square sq = new Square(4);&lt;br&gt;

	Rectangle r = sq;&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	Here variable r refers to sq as a Rectangle instance (possible because the 

	Square class derives from the Rectangle class). We can now raise the question: 

	if we run the following code

&lt;/p&gt;

&lt;blockquote&gt; double area = r.getArea();&lt;br&gt;

&lt;/blockquote&gt;

&lt;p&gt;

	then which getArea method is actually called - the Square class method or the 

	Rectangle class method?

&lt;/p&gt;

&lt;p&gt;

	The answer in this case is that the Square class method would still be called. 

	Because the Square class' getArea method 'overrides' the corresponding method 

	in the Rectangle class, calls to this method on a Square instance always 'slide 

	through' to the overriding method.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;h4&gt;&lt;a name="2"&gt;Method Hiding&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Where one method 'hides' another, the hidden method does not need to be 

	declared with any special keyword. Instead, the hiding method just declares 

	itself as 'new'. So, where the Square class hides the Rectangle class' getArea 

	method, the two methods might just be written thus:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table7"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table8"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table9"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													double getArea() // in Rectangle&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													length * width;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table10"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table11"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table12"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													new double getArea() // in Square&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													length * length;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	Note that a method can 'hide' another one without the access modifiers of these 

	methods being the same. So, for instance, the Square's getArea method could be 

	declared as private, viz:

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table13"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table14"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table15"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;private 

													new double getArea()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;return 

													length * length;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	This leads us to an important point. A 'new' method only hides a super-class 

	method with a scope defined by its access modifier. Specifically, where the 

	access level of the hiding method is 'private', as in the method just 

	described, this method only hides the super-class method for the particular 

	class in which it is defined.

&lt;/p&gt;

&lt;p&gt;

	To make this point more concrete, suppose that we introduced a further class, 

	SpecialSquare, which inherits from Square. Suppose further that SpecialSquare 

	does not overwrite the getArea method. In this case, because Square's getArea 

	method is defined as private, SpecialSquare inherits its getArea method 

	directly from the Rectangle class (where the getArea method is public).</description><guid>http://www.softxml.com/LearnTutorial.asp?id=5327089719&amp;f=c&amp;fo=tutorials</guid><category>c</category></item><item><title>Constants, Fields, Properties and Indexers</title><link>http://www.softxml.com/LearnTutorial.asp?id=16441225535&amp;f=c&amp;fo=tutorials</link><description>&lt;h4&gt;&lt;a name="1"&gt;Fields&lt;/a&gt;&lt;/h4&gt;

&lt;p&gt;

	Fields are variables associated with either classes or instances of classes. 

	There are seven modifiers which can be used in their declarations. These 

	include the four access modifiers 'public', 'protected', 'internal' and 

	'private'&amp;nbsp;and the 'new' keyword. The two remaining modifiers are:

&lt;/p&gt;

&lt;p&gt;

	&lt;b&gt;static&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	By default, fields are associated with class instances. Use of the 'static' 

	keyword, however, associates a field with a class itself, so there will only 

	ever be one such field per class, regardless of the number of the class 

	instances (and the static field will exist even if there are no class 

	instances). A static field need not be constant, however; it can be changed by 

	code. In the following code example the 'setStaticField' method illustrates 

	such a change.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table1"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table2"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table3"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													class MyClass&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;public 

													static int StaticField = 1;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;public 

													MyClass()&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;{}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;7.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;8.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;public 

													void setStaticField(int i)&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;9.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;10.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;MyClass.StaticField 

													= i;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;11.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;12.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;}&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

									&lt;/tbody&gt;

								&lt;/table&gt;

							&lt;/td&gt;

						&lt;/tr&gt;

					&lt;/tbody&gt;

				&lt;/table&gt;

			&lt;/td&gt;

		&lt;/tr&gt;

	&lt;/tbody&gt;

&lt;/table&gt;

&lt;br&gt;

&lt;p&gt;

	&lt;b&gt;readonly&lt;/b&gt;

&lt;/p&gt;

&lt;p&gt;

	Where a field is readonly, its value can be set only once, either in the class 

	declaration, or (for non-static fields only) in the class constructor. The 

	following code example (which, please note, deliberately doesn't compile) shows 

	both cases: the field StaticReadonlyInt is set in the class declaration; the 

	field readonlyString is set in the class constructor.

&lt;/p&gt;

&lt;p&gt;

&lt;/p&gt;

&lt;table align="center" border="0" cellpadding="1" cellspacing="0" width="70%" ID="Table4"&gt;

	&lt;tbody&gt;

		&lt;tr&gt;

			&lt;td bgcolor="#00008b"&gt;

				&lt;table border="0" cellpadding="0" cellspacing="0" width="100%" ID="Table5"&gt;

					&lt;tbody&gt;

						&lt;tr&gt;

							&lt;td bgcolor="#ffffff"&gt;

								&lt;table border="0" cellpadding="3" cellspacing="0" width="100%" ID="Table6"&gt;

									&lt;tbody&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;1.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;public 

													class MyClass&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;2.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;{&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;3.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;public 

													static readonly int StaticReadonlyInt = 1;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;4.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;public 

													readonly string readonlyString;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;5.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/p&gt;

											&lt;/td&gt;

										&lt;/tr&gt;

										&lt;tr valign="top"&gt;

											&lt;td width="10%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;6.&lt;/p&gt;

											&lt;/td&gt;

											&lt;td width="90%"&gt;

												&lt;p style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; PADDING-TOP: 0px"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;public 

													MyClass()&lt;/p&gt;

											&lt;/td&gt;