class  Class1

{

public:

    virtual void f()

    {

        cout << "Function f() in Class1 \n";

    }

    void g()

    {

        cout << "Function g() in Class1 \n";

    }

};

class Class2

{

public:

    virtual void f()

    {

        cout << "Function f() in Class2\n";

    }

    void g()

    {

        cout << "Function g() in Class2 \n";

    }

};

class Class3

{

    virtual void h()

    {

        cout << "Function h() in Class3\n";

    }

};

int main()

{

    Class1 object1, * p;

    Class2 object2;

    Class3 object3;

    p = &object1;

    p->f();

    p->g();

    p = (Class1*)& object2;

    p->f();

    p->g();

    p = (Class1*)& object3;

    //p->f();

    p->g();

}