// MemberFP.cpp - demonstrate use of pointers to members

#include <iostream>

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


void main () {
  std::cout << "\n  Demonstrate member pointers\n\n";


  C c;              // an object
  C* cptr = &c;     // pointer to object

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

  // declare function pointers to members
  void (C::*fptr)() = &C::mf;    // fptr is pointer to member mf()
  int  (C::*gptr)(int) = &C::mf; // gptr is pointer to member mf(int)

  // invoke each function with object and member pointer
  (c.*fptr)();               // call mf() with obj & member ptr
  int z = (c.*gptr)(y);      // call mf(y) with obj & member ptr

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

  // invoke each function with object pointer and member pointer
  (cptr->*fptr)();           // call mf() with obj ptr & member ptr
  int w = (cptr->*gptr)(z);  // call mf(z) with obj ptr & member ptr

  std::cout << "  result is: " << w << std::endl << std::endl;
}