Thread: inheritance

I have a class CGeneral. And then I have more classes CClass1, CClass2, ... Each one is a public child of CGeneral. Can I create a pointer to CGeneral which can be later casted to pointer to some of its child classes? Like:

Code:

class CGeneral {
  MethodOfParentClassCGeneral();
};

class Class1: public CGeneral {
  MethodOfClass1();
} obj;

CGeneral *pGen = (CGeneral*)&obj;
//...
//...
// now I need access to instance obj again
CClass1 *pCl1 = (CClass1*)pGen;
pCl1->MethodOfClass1();
pCl1->MethodOfParentClassCGeneral();

Yes, you can do this. Indeed this type of operations is the heart
of polymorphism. You can find a lot of detailed information in the Internet or in C++ books about polymorphism also.

You should try to avoid casting really.

Code:

CClass1 *pCl1 = (CClass1*)pGen;
// pCl1->MethodOfClass1(); // try avoid this
// pCl1->MethodOfParentClassCGeneral(); // instead use the following
pGen->MethodOfParentClassCGeneral();

Instead of casting, use the most general pointer that doesn't need to be casted. Casting itself is an abuse, something to be done perhaps when you have old code that is poorly designed, and don't have the time to do it properly.