windows 程序设计自学:窗口正中显示Hello,World

 #include <windows.h>

 LRESULT CALLBACK MyWndProc(  HWND hwnd,      // handle to window
   UINT uMsg,      // message identifier
   WPARAM wParam,  // first message parameter
   LPARAM lParam   // second message parameter
   );

 int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd )
 {
     WNDCLASS wnd;
     HWND hwnd;
     MSG msg;
     wnd.style = CS_HREDRAW | CS_VREDRAW; //水平或垂直改变窗口都被重绘 与MyWndProc的WM_PAINT消息关联
     wnd.lpfnWndProc = MyWndProc;
     wnd.cbClsExtra = ;
     wnd.cbWndExtra = ;
     wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);
     wnd.hCursor = LoadCursor(NULL, IDC_ARROW);
     wnd.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
     wnd.lpszMenuName = NULL;
     wnd.lpszClassName = "HelloClass"; //窗口类标识,用在CreateWindow的第一个参数
     wnd.hInstance = hInstance;
     if(!RegisterClass(&wnd))
     {
         MessageBox(NULL, TEXT("无法创建窗口"), TEXT("ERROR"), MB_OK|MB_ICONERROR);
         return ;
     }

     hwnd = CreateWindow("HelloClass", TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL); //第二个参数为窗口标题
     ShowWindow(hwnd, nShowCmd);
     while (GetMessage(&msg, NULL, , ))
     {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
     }
     return ;
 }

 LRESULT CALLBACK MyWndProc(  HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 {
     HDC hdc; //定义设备环境句柄
     PAINTSTRUCT ps; //绘制结构
     RECT rect; //矩形结构
     switch(uMsg)
     {
     case WM_PAINT:
     {
         hdc = BeginPaint(hwnd, &ps);
         GetClientRect(hwnd, &rect);
         DrawText(hdc, TEXT("Hello,World!"), -, &rect, DT_SINGLELINE|DT_CENTER|DT_VCENTER);
         EndPaint(hwnd, &ps);
     }
     break;
     case WM_DESTROY:
         PostQuitMessage();
         return ;
     }

     return DefWindowProc(hwnd, uMsg, wParam, lParam);
 }