Address of an object

From:
 raan <palakadan@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 01 Aug 2007 00:58:39 -0000
Message-ID:
<1185929919.417488.260280@d30g2000prg.googlegroups.com>
Please see the following program. I uses Windows XP/VS2003 as my
environment.

I have two classes inherited from a base class called Interfaces. I
have a class named General in which I have instantiated objects for A
and B. I have instantiated two objects ga, gb of type A and B
respectively in my main function. I wish ga and gb, in my main,
points to the same address space that a and b occupies.

My ultimate aim is to have () operator overloaded in class A and class
B so that I can call ga() and gb() (functors) from my main program.
Basically the main program will be replaced by another class and
should use the objects intantiated in General class to carry out its
functionality. Calling it as (*ga)() and (*gb)() doesn't look cool .
Hope you guys get the point, why I want it this way.

Is there anyway I can achieve this

#include "stdafx.h"
#include <iostream>

using namespace std;

class Interfaces
{
public:
  Interfaces(){}
 ~Interfaces(){}
};

class A : public Interfaces
{
public:
   A() {};
  ~A() {};
  void afunc()
  {
    cout << this << endl;
    cout << "a func called" << endl;
  }

};

class B: public Interfaces
{
public:
   B() {};
  ~B() {};
  void bfunc()
  {
    cout << this << endl;
    cout << "b func called" << endl;
  }
};

class General
{
  private:
  A a;
  B b;
   public:
     General() {cout << "A Addres " << &a << endl;
                cout << "B Addres " << &b <<endl;};
    ~General() {};
   void QueryInterface(int id, Interfaces *ptr)
   {
     switch(id)
     {
       case 1:
         ptr = &a;
         cout << "Ptr a "<< ptr << endl;
       break;
       case 2:
         ptr = &b;
         cout << "Ptr b "<< ptr << endl;
       break;
     }
   }
};

int _tmain(int argc, _TCHAR* argv[])
{
    General *g = new General;
    A ga;
    B gb;

    cout << "Before QI ga " << &ga << endl;
    cout << "Before QI gb " << &gb << endl;

    g->QueryInterface(1, &ga);
    g->QueryInterface(2, &gb);

    cout << "After QI ga " << &ga << endl;
    cout << "After QI gb " << &gb << endl;

    ga.afunc();
    gb.bfunc();

    getchar();

    return 0;
}

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