Abstract - Key things about Abstract Classes/Methods

Abstract Classes

• An Abstract class cannot be instantiated.

abstract class SampleAbs

{

...

}

SampleAbs instance = new SampleAbs(); // Compile Error

• It cannot be modified with the 'sealed' modifier. In other words, an Abstract Class should be inherited.
• An Abstract class may contain abstract as well as non abstract members.

Abstract Methods

• An Abstract method cannot contain a method body.

abstract class AbsClass

{

abstract void AbsMethod(); // Legal

abstract void AbsMethod()

{

... // Illegal

}

}

• An abstract method is implicitly a virtual method.
• An Abstract method can only be added in an Abstract Class.