Re: organizing application properly question

From:

David Wilkinson <no-reply@effisols.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Tue, 10 Apr 2007 05:18:23 -0500

Message-ID:

<e6VOVE1eHHA.4604@TK2MSFTNGP06.phx.gbl>

kunal s patel wrote:

Well yes i need to use the methods of CMainGui from simulation......for
reference i am writing a small application so it gives a clear idea about how
i want it to work....(please bear the variable name change...i have added
appropriate comments)

//SampleDlg.h file
#pragma once
#include "afxwin.h"
#include "Resource.h"

Class has the following additional method declarations
void addtoListBox(CString s);

//SampleDlg.cpp file
#include "stdafx.h"
#include "Sample.h"
#include "SampleDlg.h"
#include "Simulation.h"

simulation *sim; //global declaration

BOOL CSampleDlg::OnInitDialog()
{
     sim = new sim(this);
}

void CSampleDlg::addtoListBox(CString s)
{
    m_listbox.AddString(s); //Assume there is a listbox with variable
m_listbox
}

*********************************************

//simulation.h file
#include "SampleDlg.h"

class simulation
{
public:
    CSampleDlg *pmain;
    simulation(LPVOID wnd);
    void interpret(LPVOID);
};

//simulation.cpp file
#include "stdafx.h"
#include "Simulation.h"

simulation::simulation(LPVOID wnd)
{
    pmain = (CSampleDlg*)wnd;
}

void simulation::interpret(LPVOID wnd)
{
    pmain->addtoListBox("Hello");
}

I hope this makes it more clear how it works right now......but i dont want
sim to be a global variable....i want to put it into CSampleDlg.h file as a
class member and then initialize it in InitDialog and use it in
simulation.cpp file??

Now how do i do the above following??

kunal:

My impression is that you are having problems with circular includes,
and this is ahy you are resorting to global variables and violating the
type system by passing argumenets as void* and casting.

This is completely unnecessary. As Joe explained, you never need to
include A.h in B.h when the definition of class B ontains only pointers
to A. Rather you can use forward declaration.

//SampleDlg.h file
#pragma once

class simulation; // forward declaraion

class SampleDialog
{
   simulation* sim;
public:
   BOOL OnInitDialog();
};

//simulation.h
#pragma once

class CSampleDlg; // forward declaration

class simulation
{
   CSampleDlg* pmain;
public:
   simulation(CSampleDlg* wnd);
   void interpret();
};

As Joe also said, it should not be necessary for your simulation class
to know that the main window pointer is a CSampleDlg*, so you should
probably be just using a CWnd*.

You seem to be trying to learn Windows programming in C++ without a
clear grasp of C++ itself (or at least its compilation model). This is a
mistake, IMHO.

--
David Wilkinson
Visual C++ MVP