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Also note that you can only do multiple inheritance from interfaces, not abstract classes.<br />
<br />
Last, I advice you to look at this URL: <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconAbstractClassesVersusInterfaces.asp" rel="ugc">http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconAbstractClassesVersusInterfaces.asp</a>
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I am currently learning C#. I know C++ quite well, and a few of Java. <br />
I thought a C# 'interface' was similar to an 'abstract' class when I suddenly discovered that there exists two independant keywords to declare classes : 'interface' and 'abstract'.<br />
I don't really understand the notion of 'contract' in the definition of an interface.<br />
<br />
Please explain C# interfaces, in what situation they should be used, and how they differ from abstract classes.<br />

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I am currently learning C#. I know C++ quite well, and a few of Java. 
I thought a C# 'interface' was similar to an 'abstract' class when I suddenly discovered that there exists two independant keywords to declare classes : 'interface' and 'abstract'.
I don't really understand the notion of 'contract' in the definition of an interface.

Please explain C# interfaces, in what situation they should be used, and how they differ from abstract classes.


Also note that you can only do multiple inheritance from interfaces, not abstract classes.

Last, I advice you to look at this URL: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconAbstractClassesVersusInterfaces.asp

Explain Interfaces

I am currently learning C#. I know C++ quite well, and a few of Java. 
I thought a C# &#39;interface&#39; was similar to an &#39;abstract&#39; class when I suddenly discovered that there exists two independant keywords to declare classes : &#39;interface&#39; and &#39;abstract&#39;.
I don&#39;t really understand the notion of &#39;contract&#39; in the definition of an interface.

Please explain C# interfaces, in what situation they should be used, and how they differ from abstract classes.


C# is an object-oriented programming language created in conjunction with Microsoft’s .NET framework. Compilation is usually done into the Microsoft Intermediate Language (MSIL), which is then JIT-compiled to native code (and cached) during execution in the Common Language Runtime (CLR).