三、窗口与消息源代码

#include <Windows.h>

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;
	HWND hwnd;
	MSG msg;

	wndclass.style=CS_VREDRAW|CS_HREDRAW;
	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("You Should Be Under WinNT"),TEXT("Error"),MB_OK);
		return 0;
	}

	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);

	while (GetMessage(&msg,NULL,0,0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	return msg.wParam;

}

LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
{
	HDC hdc;
	PAINTSTRUCT ps;
	RECT rect;

	switch (message)
	{
	case WM_PAINT:
		hdc=BeginPaint(hwnd,&ps);
		GetClientRect(hwnd,&rect);
		DrawText(hdc,TEXT("Welcome to Windows' World!"),-1,&rect,DT_SINGLELINE|DT_VCENTER|DT_CENTER);
        EndPaint(hwnd,&ps);
		return 0;

	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hwnd,message,wParam,lParam);
}