nested switch statements

1. 語法

   switch(ch1) {
      case 'A': 
         printf("This A is part of outer switch" );
         switch(ch2) {
            case 'A':
               printf("This A is part of inner switch" );
               break;
            case 'B': /* case code */
         }
         break;
      case 'B': /* case code */
   }