Pure virtual Function
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When do we make a virtual function “pure”? What are the implications of making a function as a pure virtual function?
OR
What is a pure virtual function? When it is needed? Or Explain features of pure virtual functions. Or What is abstract class?
v A pure virtual function is a function declared in a base class that has no definition relative to the base class.
v A class containing pure virtual functions cannot be used to declare any objects of its own.
v Such classes are called the abstract base classes, which are used just as place holder.
v Pure virtual function is needed to create an abstract base class.
v If a virtual function is declared as pure, it must be redefine in each derived class else the compilation of the program is unsuccessful.
v A function is declared just only for serving purpose of as a placeholder. That function defined as “empty” in base class, which is called “do-nothing” function or “virtual function”.
v This function is defined as follows,
virtual void display ( ) = 0;
6.