CS202 4- ‹#›
nAn abstract class is a class that can only be derived from; no objects can be instantiated it.
nIts purpose is to define an interface and provide a common base class for derived classes.
nA base class becomes an abstract class by making its constructor(s) protected or by declaring a virtual function pure: virtual void statement()=0;
nDerived classes must implement all pure virtual functions. If a derived class does not implement these functions, then it becomes an abstract class as well.
nAbstract classes are not required to implement their pure virtual functions.
Abstract Base Classes