The switch Statement

Objectives

1. Examine the switch statement.

Notes

• Reference/tutorial
• I would like to count the number of items in each different form (Froze, Fresh, ...).
  • But unfortunately I do not know all of the classes.
• I could use

      private static void CountTypes() {
           if(fruitType.equals("Fresh")) {
               freshCount ++;
           }
  
           if (fruitType.equals("Frozen")) {
               frozenCount++;
           }
      } 

• But unfortunately this does not identify missing classes.
• I can change it just a bit

           if(fruitType.equals("Fresh")) {
               freshCount ++;
           } else if (fruitType.equals("Frozen")) {
               frozenCount++;
           } else if (fruitType.equals("Canned")) {
               cannedCount++;
           } else if (fruitType.equals("Dried")) {
               driedCount++;
           } else if (fruitType.equals("Juice")) {
               juiceCount++;
           } else {
               System.out.printf("%s is unknown\n", fruitType);
           } 

• But that is really ugly.
• The Switch statement

  switch (expression) {
      case literal1: 
          statements;
          break;
      case literal2: 
          statements;
          break;
      ...
      default:
          statements;
          break;
  }
      

• It is cleaner
• It will identify if you have duplicate cases.

      private static void CountTypes() {
  
           switch (fruitType) {
               case "Fresh":
                   freshCount++;
                   break;
               case "Frozen":
                   frozenCount++;
                   break;
               case "Canned":
                   cannedCount++;
                   break;
               case "Dried":
                   driedCount++;
                   break;
               case "Juice":
                   juiceCount++;
                   break;
               default:
                   System.out.printf("%s is an unknown type\n",fruitType);
                   break;
           }
  
      }