C / C++ / MFC

class A;

class B
{
    A*  m_pA;
...
};

#include "a.h"

class A;
class B
{    
A*  m_pA;
...
};

class A
{    
...
};

class A;
class B
{    
A*  m_pA;
...
};

class Child;
class Parent {

//...

    Child    *ChildrenList;

};

class Child {

    Parent    *Mother;
    Parent    *Father;

};

#pragma once 

void CMyDialog::OnOK()
{
    CDialog::OnOK();  //  Wizard generated code
}

BOOL CMyDlg::PreTranslateMessage(MSG* pMsg) 
{
	// Check for a keypress
	if (pMsg->message == WM_KEYDOWN)
	{
                // Check for CR and ESC
		if ((pMsg->wParam == 13) || (pMsg->wParam == 27))
		{
                        // Soak them up, no further processing
			return TRUE;
		}
	}

	return CDialog::PreTranslateMessage(pMsg);
}