/*------------------------------------------------------------   HELLOWIN.C -- Displays "Hello, Windows 98!" in client area                 (c) Charles Petzold, 1998  ------------------------------------------------------------*/#include <windows.h>LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,                    PSTR szCmdLine, int iCmdShow){     // 第零步，提前定义变量     static TCHAR szAppName[] = TEXT ("HelloWin") ; // 窗口的类名     HWND         hwnd ; // 窗口创建后得到的句柄     MSG          msg ;  // 消息循环用的消息变量（就一个）     // 第一步，定义窗口类     WNDCLASS     wndclass ;     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;     wndclass.lpfnWndProc   = WndProc ; // 重要属性：窗口函数（回调函数）     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 ; // 重要属性：窗口类名称     // 第二步，注册窗口类     if (!RegisterClass (&wndclass))     {          MessageBox (NULL, TEXT ("This program requires Windows NT!"),                       szAppName, MB_ICONERROR) ;          return 0 ;     }     // 第三步，创建窗口类     hwnd = CreateWindow (szAppName,                  // window class name                          TEXT ("The Hello Program"), // window caption                          WS_OVERLAPPEDWINDOW,        // window style                          CW_USEDEFAULT,              // initial x position                          CW_USEDEFAULT,              // initial y position                          CW_USEDEFAULT,              // initial x size                          CW_USEDEFAULT,              // initial y size                          NULL,                       // parent window handle                          NULL,                       // window menu handle                          hInstance,                  // program instance handle                          NULL) ;                     // creation parameters     // 第四步，显示窗口     ShowWindow (hwnd, iCmdShow) ;      // 第五步，刷新窗口     UpdateWindow (hwnd) ;     // 第六步，消息循环     while (GetMessage (&msg, NULL, 0, 0))     {          TranslateMessage (&msg) ;          DispatchMessage (&msg) ;     }     // 最后一步，将最后一个消息的wParam参数返回给main函数当作函数结果     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:          PlaySound (TEXT ("hellowin.wav"), NULL, SND_FILENAME | SND_ASYNC) ; // API          return 0 ;               case WM_PAINT:          hdc = BeginPaint (hwnd, &ps) ; // API                    GetClientRect (hwnd, &rect) ; // API                    DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,                    DT_SINGLELINE | DT_CENTER | DT_VCENTER) ; // API                    EndPaint (hwnd, &ps) ; // API          return 0 ;               case WM_DESTROY:          PostQuitMessage (0) ; // API          return 0 ;     }     return DefWindowProc (hwnd, message, wParam, lParam) ; // API}