Question

Let us say that I have a class A which is extended by B and C. Now, for want of polymorphism, I use base class pointer to point to the derived class object.

A *a = new B(); OR A *a= new C();

Now, let us say that I have executed few statements. now, I am interested in identifying the type of the object that the base class pointer is pointing to. How can this be done?

Answer 1

The direct way would be to use dynamic_cast:

B* b = dynamic_cast<B*>( a );
if( b != 0 ) {
  // the object can be cast to class B safely
}

however the real answer is you don’t need to when you do polymorphism right – you have to use virtual functions and implement them appropriately in derived classes so that you can blindly call them and have the right code executed.