Re: Address of an object

From:

"Alf P. Steinbach" <alfps@start.no>

Newsgroups:

comp.lang.c++

Date:

Wed, 01 Aug 2007 03:59:01 +0200

Message-ID:

<13avq3em469al9c@corp.supernews.com>

* raan:

#include "stdafx.h"

This header is not standard C++.

#include <iostream>

using namespace std;

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

This class serves no useful purpose, and in fact, you're not using it.

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;
  }
};

These two classes have nothing in common (except the unused Interface
base class).

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;
     }
   }
};

The QueryInterfaces function reports only whether you passed in 1 or 2
as argument, what's the use of that?

int _tmain(int argc, _TCHAR* argv[])

This is not standard C++. In standard C++ use 'main'. Like

int main()

{
    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;
}

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?