// Textbook fragment 01.05
    switch (d) {
      case MON:
        System.out.println("This is tough.");
        break;
      case TUE:
        System.out.println("This is getting better.");
        break;
      case WED:
        System.out.println("Half way there.");
        break;
      case THU:
        System.out.println("I can see the light.");
        break;
      case FRI:
        System.out.println("Now we are talking.");
        break;
      default:
        System.out.println("Day off!");
        break;
    }