#include <iostream>
using std::cout;
using std::endl;

class B {
public:
  int i;
  virtual void print()
  { cout << "i value is " << i 
      << " inside object of type B\n\n"; }
};

class D: public B {
public:
  void print()
  { cout << "i value is " << i 
      << " inside object of type D\n\n"; }
};

int main()
{
  B b;
  B *pb;
  D d;
  b.i = 3; // initilise i values in objects 
  d.i = 5;
  pb = &b;
  cout << "pb now points to b\n";
  cout << "Calling pb->print()\n";
  pb->print();    // uses B::print()
  pb = &d;
  cout << "pb now points to d\n";
  cout << "Calling pb->print()\n";
  pb->print();    // uses D::print()
  return 0;
}