矩形应用，画一个3行3列的矩形组合

#include 
      
       LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;#define edge 30 //矩形边长HBRUSH hbrush[2];//刷子数组void paint(HDC hdc);//画图声明int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,PSTR szCmdLine, int iCmdShow){     static TCHAR szAppName[] = TEXT ("HelloWin") ;     HWND         hwnd ;                     MSG          msg ;                    WNDCLASS     wndclass ;                wndclass.style         = CS_HREDRAW | CS_VREDRAW ;     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))return 0 ;                 hwnd = CreateWindow (szAppName,                                            TEXT ("一个简单的Win32程序"),                           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;     switch (message)     {               case WM_PAINT:      hdc=BeginPaint(hwnd,&ps);      paint(hdc);      EndPaint(hwnd,&ps);      return 0;           case WM_DESTROY:         DeleteObject(hbrush[0]);         DeleteObject(hbrush[1]);          PostQuitMessage (0) ; //在消息队列中插入一条“退出”消息          return 0 ;     }     return DefWindowProc (hwnd, message, wParam, lParam);//执行默认的消息处理}void paint(HDC hdc){        int i,j;    hbrush[0]=CreateSolidBrush(RGB(255,0,0));    hbrush[1]=CreateSolidBrush(RGB(255,255,0));              for(j=0;j<3;j++) //行            for(i=0;i<3;i++)//列        {                if(j%2==0)                {                Sleep(50);                SelectObject(hdc,hbrush[0]);                    Rectangle(hdc,i*edge,j*edge,(i+1)*edge,(j+1)*edge);                    }                else                {                    Sleep(100);                SelectObject(hdc,hbrush[1]);                    Rectangle(hdc,i*edge,j*edge,(i+1)*edge,(j+1)*edge);                    }        }}