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== What is a C# Abstract Class? ==

In the examples we have looked at so far in this book we have created classes which could be both instantiated as objects and used as a base class from which to derive classes. Often a base class is not intended to be instantiated and is provided solely for the purpose of providing an outline for subclasses. Such a class is known as an ''abstract class''. An abstract class cannot be instantiated as an object and is only provided for the purpose of deriving subclasses.