MFC_1——采用windows API函数来生成一个窗口显示helloword

//采用windows API函数来生成一个窗口显示helloword：
#include <windows.h>    

LRESULT CALLBACK myWndProc(HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam);   

//进入WinMain函数
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
	const static TCHAR appName[] = TEXT("Hello world"); 

	//初始化WNDCLASSEX，调用RegisterClassEx函数注册窗口类
	WNDCLASSEX myWin;
	myWin.cbSize = sizeof(myWin);
	myWin.style = CS_HREDRAW | CS_VREDRAW;
	myWin.lpfnWndProc = myWndProc;
	myWin.cbClsExtra = 0;
	myWin.cbWndExtra = 0;
	myWin.hInstance = hInstance;
	myWin.hIcon = 0;
	myWin.hIconSm  = 0;
	myWin.hCursor = 0;
	myWin.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
	myWin.lpszMenuName = 0;
	myWin.lpszClassName = appName;
	//Register ,调用RegisterClassEx函数注册窗口类
	if (!RegisterClassEx(&myWin)) return 0;
	const HWND hWindow = CreateWindow(
		appName,
		appName,
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		0,
		0,
		hInstance,
		0);
	//调用ShowWindow和UpdateWindow函数显示并更新窗口
	/*进入消息循环。关于消息循环再简单说下，Windows应用程序是消息驱动的，
	系统或用户让应用程序进行某项操作或完成某个任务时会发送消息，
	进入程序的消息队列，然后消息循环会将消息队列中的消息取出，
	交予相应的窗口过程处理，此程序的窗口过程函数就是myWndProc函数，
	窗口过程函数处理完消息就完成了某项操作或任务。
	本例是要显示“HELLO WORLD”字符串，UpdateWindow函数会发送WM_PAINT消息，
	但是此消息不经过消息队列而是直接送到窗口过程处理，
	在窗口过程函数中最终绘制了“HELLO WORLD”字符串。*/
	ShowWindow(hWindow,iCmdShow);
	UpdateWindow(hWindow);
	{
		MSG msg;
		while(GetMessage(&msg,0,0,0))
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
		return (int)msg.wParam;
	}
}      

LRESULT CALLBACK myWndProc(HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam)
{
	if (msg==WM_PAINT)
	{
		PAINTSTRUCT ps;
		const HDC hDC = BeginPaint(hWindow,&ps);
		RECT rect;
		GetClientRect(hWindow,&rect);
		DrawText(hDC,TEXT("HELLO WORLD"),-1,&rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER);
		EndPaint(hWindow,&ps);
		return 0;
	}
	else if (msg==WM_DESTROY)
	{
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hWindow,msg,wParam,lParam);
}