// A1c.cpp -- variation c on Question #1

#include <iostream.h>

class B { public: virtual void mf(int n); protected: int state; };

void B::mf(int n) {
  cout << "  B::mf(" << n << ") invoked\n"; state = n;
}

class D : public B { public: void mf(int n); };

void D::mf(int n) {
  cout << "  D::mf(" << n << ") invoked\n"; state = -n;
}

void main() {

  D d1;                 // compiler gen'd void ctor for D called
				// which calls compiler gen'd void ctor for B
  B *bptr = new D(d1);  // memory allocated to hold a D object
                        // on heap, initialized with Compiler
                        // generated copy ctor for D which calls
                        // compiler generated base void ctor
  bptr->mf(3);          // D:mf(3) is invoked polymorphically;
				// since we added virtual qualifier to B::mf
}