First Win32 App, 第一个Win32 GUI程序

#include <windows.h>  LONG WINAPI WndProc(HWND, UINT,WPARAM,LPARAM); //回调原型  int WINAPI WinMain(              HINSTANCE         hInstance,        HINSTANCE         hPrevInstance,        LPSTR         lpCmdLine,        int         nCmdShow        ) {   WNDCLASS wc;  HWND hwnd;  MSG msg;   //1.设计窗体  wc.style = 0;  wc.lpfnWndProc = (WNDPROC)WndProc;  wc.cbClsExtra = 0;  wc.cbWndExtra = 0;  wc.hInstance = hInstance;  wc.hIcon = LoadIcon(NULL,IDI_WINLOGO);  wc.hCursor = LoadCursor(NULL,IDC_ARROW);  //wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);  wc.hbrBackground = (HBRUSH)(COLOR_GRAYTEXT);    wc.lpszMenuName = NULL;  wc.lpszClassName = "MyWndClass";   RegisterClass(&wc);  //2.注册窗体   hwnd = CreateWindow( //3.创建窗体    "MyWndClass",   //WNDCLASS NAME    "SDK APPLICATION标题",  //WINDOW TITLE    WS_OVERLAPPEDWINDOW, //WINDOW STYLE    CW_USEDEFAULT,   //Horizontal position    CW_USEDEFAULT,   //Vertical position    CW_USEDEFAULT,   //Initial width    CW_USEDEFAULT,   //Initial height    HWND_DESKTOP,   //Handle of parent window    NULL,     //Menu handle    hInstance,    //Application's instance handle    NULL     //Window-creation data   );    ShowWindow(hwnd,nCmdShow); //4.显示更新窗体  UpdateWindow(hwnd);   while(GetMessage(&msg,NULL,0,0)){  //5.消息循环   TranslateMessage(&msg);   DispatchMessage(&msg);  }  return msg.wParam; }   LRESULT CALLBACK WndProc(HWND hwnd, UINT message,WPARAM wParam,LPARAM lParam){    PAINTSTRUCT ps;  HDC hdc;  switch(message){  case WM_PAINT:   hdc=BeginPaint(hwnd,&ps);   Ellipse(hdc,0,0,200,100);   EndPaint(hwnd,&ps);   return 0;     case WM_DESTROY:   PostQuitMessage(0);   return 0;  }  return DefWindowProc(hwnd,message,wParam,lParam); }