void flip_full_screen()
static void flip_full_screen()
void flip_full_screen(){    if (is_full_screen()) {	ShowWindow(hwnd, SW_RESTORE);    } else if (IsZoomed(hwnd)) {	make_full_screen();    } else {	SendMessage(hwnd, WM_FULLSCR_ON_MAX, 0, 0);	ShowWindow(hwnd, SW_MAXIMIZE);    }}