#include <iostream.h>

class myOldClass
{
public:
   int i1;

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

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

   cout << "Invoking A.funct1(4)" << endl;
   A.func1(4);
   cout << endl;

   cout << "Invoking B.funct1(4)" << endl;
   B.func1(4);
   cout << endl << endl;

   // This is illegal:
   // ptr2 = &A;

   // *************************************************************************
   // This is the interesting part: which function would ptr1->func1() pick ?
   //  
   //   A is a myOldClass variable that has it's own func1()
   //   B is a myNewClass variable that has it's own func1()
   //   ptr1 can point to a myOldClass or a myNewClass variable
   //   Which function will ptr1->func1() invoke ???
   //
   // *************************************************************************
   ptr1 = &A;
   cout << "ptr1 = &A; Invoking ptr1->func1(4)" << endl;
   ptr1->func1(4);
   cout << endl;

   ptr1 = &B;
   cout << "ptr1 = &B; Invoking ptr1->func1(4)" << endl;
   ptr1->func1(4);
}