Hello
i've compiled the following app:

main.cpp:
Code:
#include <afxwin.h>
#include "resource.h"

class C_MyApp : public CWinApp 
{ 
public:
	BOOL InitInstance(); 
}; 

class C_MainFrame : public CFrameWnd 
{ 
public:
	C_MainFrame();
private:
	int m_nBeeps;
	void OnOneBeep(); // declare fxns that respond
	void OnFourBeeps(); // to menu items
	void OnGreeting();
	void OnTimer(UINT); // declare fxn that responds
	// to WM_TIMER messages
	CMenu Menu;
	DECLARE_MESSAGE_MAP()
};

BEGIN_MESSAGE_MAP(C_MainFrame, CFrameWnd) // define message map
	ON_COMMAND(ID_ONE_BEEP, OnOneBeep) // WM_COMMAND messages
	ON_COMMAND(ID_FOUR_BEEPS, OnFourBeeps) // are from menu items
	ON_COMMAND(ID_GREETING, OnGreeting)
	ON_WM_TIMER() // for WM_TIMER message
END_MESSAGE_MAP()

C_MainFrame::C_MainFrame() 
{
	Menu.LoadMenu(IDR_MENU1);
	CRect WindowRect(100, 150, 600, 400);
	this->SetMenu(&Menu);
	HBRUSH hredBrush = CreateSolidBrush(RGB(255, 0, 0));
	CString MyWindowClass = AfxRegisterWndClass(
		CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW,
		AfxGetApp()->LoadCursor(IDC_CURSOR1), hredBrush,
		AfxGetApp()->LoadIcon(IDI_ICON1));
	Create(MyWindowClass, L"Main Window C", WS_CAPTION | WS_SYSMENU | //"Bitwise-OR" all
		WS_VSCROLL | WS_HSCROLL | //attribute styles
		WS_SIZEBOX, WindowRect);
	//Create(NULL, L"Menus - Example A", WS_OVERLAPPEDWINDOW,
	//	WindowRect, NULL, MAKEINTRESOURCE(IDR_MENU2));
	LoadAccelTable(MAKEINTRESOURCE(IDR_ACCELERATORS));
	this->SetMenu(&Menu);
	m_nBeeps = 0;
	
}

BOOL C_MyApp::InitInstance()
{
	m_pMainWnd = new C_MainFrame;
	m_pMainWnd->ShowWindow(m_nCmdShow);
	return TRUE;
}
C_MyApp theApp;

void C_MainFrame::OnOneBeep()
{
	::MessageBeep(0);
}

void C_MainFrame::OnFourBeeps()
{
	SetTimer(1, 200, NULL);
}

void C_MainFrame::OnGreeting()
{
	int MyChoice = MessageBox(L"Hello there!\nDo you want four beeps?",
		L"Greeting", MB_ICONEXCLAMATION | MB_YESNOCANCEL);
	if (MyChoice == IDYES)
		OnFourBeeps();
}

void C_MainFrame::OnTimer(UINT nID)
{
	if (m_nBeeps == 4)
	{
		KillTimer(1);
		m_nBeeps = 0;
		return;
	}
	else
	{
		::MessageBeep(0);
		m_nBeeps++;
	}
}
resource.rc:
Code:
// Microsoft Visual C++ generated resource script.
//
#include "resource.h"
#include "winres.h"


/////////////////////////////////////////////////////////////////////////////
//
// Icon
//

// Icon with lowest ID value placed first to ensure application icon
// remains consistent on all systems.
IDI_ICON1               ICON                    "icon1.ico"


/////////////////////////////////////////////////////////////////////////////
//
// Cursor
//

IDC_CURSOR1             CURSOR                  "cursor1.cur"


/////////////////////////////////////////////////////////////////////////////
//
// Menu
//

IDR_MENU1 MENU
BEGIN
    POPUP "One Four Beeps"
    BEGIN
        MENUITEM "One Beep",                    ID_ONE_BEEP
        MENUITEM "Four Beeps",                  ID_FOUR_BEEPS
    END
    MENUITEM "Greeting",                    ID_GREETING
END


/////////////////////////////////////////////////////////////////////////////
//
// Accelerator
//

IDR_ACCELERATORS ACCELERATORS
BEGIN
    "g",            ID_ONE_BEEP,            ASCII,  NOINVERT
    "G",            ID_FOUR_BEEPS,          ASCII,  NOINVERT
    VK_RETURN,      ID_ONE_BEEP,            VIRTKEY, NOINVERT
END
resource.h:
Code:
//{{NO_DEPENDENCIES}}
// File di inclusione generato con Microsoft Visual C++.
// Utilizzato da resource.rc
//
#define VS_VERSION_INFO                 1
#define IDI_ICON1                       101
#define IDR_MENU2                       101
#define IDC_CURSOR1                     102
#define IDR_MENU1                       103
#define IDR_ACCELERATORS                105
#define ID_ONE_BEEP                     106
#define ID_FOUR_BEEPS                   107
#define ID_GREETING                     108
The work correctly in Release Mode but in debug mode i will get the following assertion:

Code:
Debug Assertion Failed!

Program: C:\WINDOWS\SYSTEM32\mfc140ud.dll
File: d:\a01\_work\38\s\src\vctools\VC7Libs\Ship\ATLMFC\Src\MFC\winfrm.cpp
Line: 2592
What's the problem? How could i check the meaning of the assertion?