在 case 语句中使用标签

在 case 关键字后显示的标签不能在 switch 语句的外部显示。（此限制也适用于 default 关键字。）下面的代码片段演示了 case 标签的正确用法：

// Sample Microsoft Windows message processing loop.
switch( msg )
{
   case WM_TIMER:    // Process timer event.
      SetClassWord( hWnd, GCW_HICON, ahIcon[nIcon++] );
      ShowWindow( hWnd, SW_SHOWNA );
      nIcon %= 14;
      Yield();
      break;

   case WM_PAINT:
      // Obtain a handle to the device context.
      // BeginPaint will send WM_ERASEBKGND if appropriate.

      memset( &ps, 0x00, sizeof(PAINTSTRUCT) );
      hDC = BeginPaint( hWnd, &ps );

      // Inform Windows that painting is complete.

      EndPaint( hWnd, &ps );
      break;

   case WM_CLOSE:
      // Close this window and all child windows.

      KillTimer( hWnd, TIMER1 );
      DestroyWindow( hWnd );
      if ( hWnd == hWndMain )
         PostQuitMessage( 0 );  // Quit the application.
      break;

   default:
      // This choice is taken for all messages not specifically
      //  covered by a case statement.

      return DefWindowProc( hWnd, Message, wParam, lParam );
      break;
}

请参见

参考

标记语句