C / C++ / MFC

int val; //find the length of this int
int len = 0;

for (int i = val;i;i = i / 10)
    len++

BOOL CALLBACK MyDlgWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_INITDIALOG:
        // Setup your dialog to display whatever...
        return TRUE;

    case WM_CLOSE:
        DestroyWindow(ghWnd); 
        ghWnd = NULL;
        return TRUE;

    case WM_DESTROY:
        RegSave(hWnd);
        PostQuitMessage (0);
        break;
    }
    
    return FALSE;
}

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
    MSG msg;
    BOOL bRet;
    
    ghWnd = CreateDialog (hInstance, MAKEINTRESOURCE(IDD_MAIN), NULL, MyDlgWndProc);
    ShowWindow (ghWnd, SW_SHOW);
    
    while ( (bRet = GetMessage(&msg, NULL, 0, 0)) != 0 ) 
    { 
        if (bRet == -1 )
        {
            // handle the error and possibly exit
        }

        // Must first check to see if the dialog exists,
        // then check to see if the message is intended for the dlg.
        // (IsDialogMessage() will perform the necessary
        //  Translate/Dispatch for us)
        //
        else if (!IsWindow(ghWnd) || !IsDialogMessage(ghWnd, &msg)) 
        { 
            TranslateMessage(&msg); 
            DispatchMessage(&msg); 
        } 
    }     
    return msg.wParam;
}