#include<iostream>
    using namespace std;
    
    class A
    {
    public:
    	virtual void doSomething()
        {
            std::cout<<"\nIn A::doSomething()";
        }
    };
    
    class B : public A
    {
    public:
    	virtual void doSomething()
        {
            std::cout<<"\nIn B::doSomething()";
        }
    };
    

    
    int main()
    {
    	B b;
        A obj;
    	A* a = &b;
      	a->doSomething();

        a = &obj;
        a->doSomething();

    	return 0;
    }