What is an abstract class:  Abstract class is stated as an abstract concept that cannot be instantiated or comparing to interface this can have some implementation and interface cannot. Some points for abstract class are given below:

:  An object of abstract class is not created it can be inherited only in a below class.

:  Usually abstract classes have base implementation & then child classes derive from the abstract class to make the class concrete.

Thus Abstract class is a class which cannot be instantiated; Abstract exists extensively for inheritance & it must be inherited. There are scenarios where it is useful to define classes which are not intended to instantiate, such classes usually are used as base-classes in inheritance hierarchies, and these are called such classes' abstract classes.    

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