int w = 8;                       switch (w){    case 0:    System.out.println("今天是星期日");                     break;    case 1:    System.out.println("今天是星期一");                     break;    case 2:    System.out.println("今天是星期二");                     break;    case 3:    System.out.println("今天是星期三");        break;            default:    System.out.println("输入有误");        break;            }