#include <iostream.h>

class myOldClass
{
public:
   int i1;

   virtual void func1(int i)
   {
      cout << "Calling myOldClass.func1(int)...\n";
      i1 = i1 + i*i;
   }
};

class myNewClass : public myOldClass
{
public:
   int i2;

   virtual void func1(int i)
   {
      cout << "Calling myNewClass.func1(int)...\n";
      i2 = i2 + 1000*i;
   }
};

int main(int argc, char *argv[])
{
   myOldClass A;
   myOldClass *ptr1;
   myNewClass B;
   myNewClass *ptr2;

   myOldClass *ptr;

   A.i1 = 0;
   B.i1 = B.i2 = 0;

   // *************************************************************************
   // Function polymorphism
   // *************************************************************************
   ptr = &A;
   cout << "ptr = &A; Invoking ptr->func1(4)" << endl;

   ptr->func1(4);      // The same expression invoke func1() in myOldClass

   cout << endl;

   ptr = &B;

   cout << "ptr = &B; Invoking ptr->func1(4)" << endl;

   ptr->func1(4);      // The same expression invoke func1() in myNewClass

}