#include <iostream>

using namespace std;

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 {
public:
    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(); // Abnormal program termination;
    p->g();
//  p->h(); // h() is not a member of Class1;
    return 0;
}