Classes derived from the abstract class must implement the pure virtual function or they, too, are abstract classes. Consider the example presented in [Virtual functions] (../cpp/virtual-functions.md) ...

virtual void display ()=0; // Pure Virtual Function / Do Nothing Function. // This function of the Base Class should be overriden by the derived classes of the Abstract Base Class.

Apparently, it's not possible to create a collection with an abstract type in STL. How do I go around the problem of creating a collection with a base abstract type and using that collection with ...