///////////////////////////////////////////////////////////////
// memptr.cpp - demonstrate use of pointers to members       //
//                                                           //
// Jim Fawcett, CSE687 - Object Oriented Design, Spring 04   //
///////////////////////////////////////////////////////////////

#include <iostream>
using namespace std;

class C {
  public:
  // defining two overloaded functions
    void mf() { cout << "this is mf()" << endl; }
     int mf(int x)
        { cout << "this is mf(int x)" << endl; return 2*x; }
};

int main () {
  
  cout << "\n\ntesting member pointers\n\n";

//---< ordinary pointers access any accessible member of specific object >---

  C c;              // an object
  C* cptr = &c;     // ordinary pointer to object
                    // - points to one specific object
                    // - can use any accessible member

// invoking each function through ordinary pointer to object
  cptr->mf();
  int x = 1;
  int y = cptr->mf(x);
  cout << "result is: " << y << endl << endl;

//----< member pointer accesses specific member of any instance >------------

  void (C::*fptr)() = &C::mf;  // fptr is pointer to member mf()
                               // - points to specific member of any instance
  int  (C::*gptr)(int) = &C::mf; 
                               // gptr is pointer to member mf(int)
                               // - points to specific member of any instance

  (c.*fptr)();               // call mf() with obj & member ptr
  int z = (c.*gptr)(y);      // call mf(y) with obj & member ptr

  cout << "result is: " << z << endl << endl;

  (cptr->*fptr)();           // call mf() with obj ptr & member ptr
  int w = (cptr->*gptr)(z);  // call mf(z) with obj ptr & member ptr

  cout << "result is: " << w << endl << endl;
  return 0;
}