C / C++ / MFC

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	HDC hdc = ::GetDC(hwnd);
	HPEN pen = ::CreatePen(PS_SOLID, 3, RGB(255, 0, 0));
	HGDIOBJ old;
	old = ::SelectObject(&hdc, pen);

	switch (message)
	{
	case WM_DESTROY:

		PostQuitMessage (0) ;
		return 0 ;
	case WM_LBUTTONDOWN:
		::TextOut(hdc, 100, 100, TEXT("Hello Windows"), 13);
		::SelectObject(hdc, old);
		return 0;

	}
	ReleaseDC (hwnd, hdc) ;

	return ::DefWindowProc (hwnd, message, wParam, lParam) ;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
					PSTR szCmdLine, int iCmdShow)
{

	static TCHAR szAppName[] = TEXT ("HelloWin") ;		

	WNDCLASS     wndclass ;
	wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
	wndclass.lpfnWndProc   = WndProc ;				 
	wndclass.cbClsExtra    = 0 ;
	wndclass.cbWndExtra    = 0 ;
	wndclass.hInstance     = hInstance ;			
	wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;	
	wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;		
	wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH);	
	wndclass.lpszMenuName  = NULL ;
	wndclass.lpszClassName = szAppName;				

	if (!RegisterClass (&wndclass))
	{
		MessageBox (NULL, TEXT ("RegisterClass Fail!"), 
			szAppName, MB_ICONERROR) ;
		return 0 ;
	}


	HWND hwnd ;
	hwnd = CreateWindow (szAppName,		
		TEXT ("The Hello Program"),		
		WS_OVERLAPPEDWINDOW,		
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		NULL,
		NULL,
		hInstance,			
		NULL);

	ShowWindow (hwnd, iCmdShow) ;
	UpdateWindow (hwnd) ;


	MSG          msg ;
	while (GetMessage (&msg, NULL, 0, 0))	
	{
		TranslateMessage (&msg) ;		
		DispatchMessage (&msg) ;		
	}
	return msg.wParam ;
}