gistfile1.cpp

class A
{
public:
        A();
        ~A();
        virtual void Afoo();
}

class A1 : public A
{

public:
        A1();
        ~A1();
        virtual void Afoo();
        void A1foo();
}

void foo(A *pa)
{
        A1 *pa1 = (A1 *)(pa);
        pa1->A1foo();
        pa1->Afoo();
        delete pa1;
}