windows 经典程序，回想起当初写这个程序时，心里多么的复杂呀

#include <windows.h>
LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPreInstance,PSTR szCmdLine,int iCmdShow)
{static TCHAR szAppName[]=TEXT("HelloWin32");HWND hwnd;MSG msg;WNDCLASS wndclass;wndclass.style         =CS_HREDRAW|CS_VREDRAW;wndclass.lpfnWndProc   =(WNDPROC)WndProc;    //windows procedurewndclass.cbClsExtra    =0;wndclass.cbWndExtra    =0;wndclass.hInstance     =hInstance;wndclass.hIcon         =LoadIcon(NULL,IDI_APPLICATION);//load an icon for use by programwndclass.hCursor       =LoadCursor(NULL,IDC_ARROW);    //load cursor for use by programwndclass.hbrBackground =(HBRUSH)GetStockObject(WHITE_BRUSH); //Obtains a graphic object ,in this case //   a brush used for painting the window's backgroundwndclass.lpszMenuName  =NULL;wndclass.lpszClassName =szAppName;if(!RegisterClass(&wndclass))  //Register a window class for the program's window{MessageBox(NULL,TEXT("This program requires Windows NT!"),szAppName,MB_ICONERROR);return 0;}hwnd=CreateWindow(szAppName,                   //window class nameTEXT("the hello program"),   //window captionWS_OVERLAPPEDWINDOW,         //   window styleCW_USEDEFAULT,               //initial x positionCW_USEDEFAULT,               //initial y POSITIONCW_USEDEFAULT,               // inital x sizeCW_USEDEFAULT,               //initial y sizeNULL,                        // parent  window handleNULL,                        //  window menu handlehInstance,                   // window    instance handleNULL                         // creationg parameters );ShowWindow(hwnd,iCmdShow);  //Shows the window on the screen.UpdateWindow(hwnd);          //Directs the window to paint itself.while (GetMessage(&msg,NULL,0,0))    //Obtains a message from the message queue.{TranslateMessage(&msg);   //Translates some keyboard messagesDispatchMessage(&msg);    //Sends a message to a window procedure}return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
{HDC hdc;PAINTSTRUCT ps;RECT rect;switch (message){case WM_CREATE:return 0;case WM_PAINT:hdc=BeginPaint(hwnd,&ps);   //Initiates the beginning of window painting.GetClientRect(hwnd,&rect);  //Obtains the dimensions of the window's client areaDrawText(hdc,TEXT("hello win"),-1,&rect,DT_SINGLELINE|DT_CENTER|DT_VCENTER);EndPaint(hwnd,&ps);    //Ends window painting.return 0;case WM_DESTROY:PostQuitMessage(0);     //Inserts q "quit" message into the message queuereturn 0;default:break;}return DefWindowProc(hwnd,message,wParam,lParam); //Performs default default processing of message
}