C / C++ / MFC

le* first = list->head;
le* second = list->head ? list->head->next;
 
while(second != first && second != NULL) {
    second = second->next;
    if(second != first && second != NULL) {
        second = second->next;
        first = first->next;
    }
}
 
if(second == NULL)
    printf("No cycle\n");
else
    printf("There is a cycle at %p (v = %d)\n", second, second->value);

• Instance handle (base address of executable/DLL)
• Style bits (here CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS)
• Cursor handle
• Background brush handle (COLOR_WINDOW + 1)
• Icon handle

BOOL CMyWnd::PreCreateWindow(CREATESTRUCT& cs)
{
   WNDCLASS wc = { 0 };
  
   wc.style = CS_HREDRAW | CS_VREDRAW;
   wc.lpfnWndProc = DefWindowProc;
   wc.hInstance = AfxGetInstanceHandle();
   wc.hIcon = ::LoadIcon( IDR_MAINFRAME );
   wc.hCursor = AfxGetApp()->LoadStandardCursor( IDC_ARROW );
   wc.hbrBackground = (HBRUSH) ( COLOR_WINDOW + 1 );
   wc.lpszMenuName = NULL;
   wc.lpszClassName = _T( "Your Class Name Here" );
 
   if ( !AfxRegisterClass( &wc ) )
      return FALSE;
 
   cs.lpszClass = wc.lpszClassName;
 
   return TRUE;
}

HWND hWnd = ::FindWindow(NULL, "Window name");