/*
 *  ====================================================================================
 *  DemoSwitch.java: The switch (or case) statement provides a mechanism for determining
 *  which statements are to be executed depending on a variable's value matching a label.
 *  The body of  switch statement is known as a switch block.
 *
 *    --  Any statement immediately contained by the switch block may be labeled
 *        with one or more case or default labels.
 *    --  The switch statement evaluates its expression and executes the
 *        appropriate case.
 *    --  default is used for the else situation.
 *  
 *  Note. In the early version of Java the selection variable could only be int or
 *  char datatype. Now it can also be an enum type (see the section on enumerated
 *  types for an example.
 *  
 *  Written By: Mark Austin                                                 October 2008
 *  ====================================================================================
 */

public class DemoSwitch {
   public static void main ( String [] args ) {

      // Part 1: Set an int variable value ....

      int i = 1;

      switch (i) {
         case 1:
              System.out.println("You typed a 1");
              break;
         case 2:
              System.out.println("You typed a 2");
              break;
         default:
              System.out.println("That was an invalid entry.");
      };

      // Part 2: Set a char value ....

      char cA = 'A';

      switch ( cA ) {
         case 'A':
              System.out.println("You selected the letter A");
              break;
         case 'B':
              System.out.println("You selected the letter B");
              break;
         default:
              System.out.println("That was an invalid entry.");
      };

      // Part 3: Case statements can be bundled into groups ...

      char cB = 'a';
      switch ( cB ) {
         case 'A':
         case 'B':
              System.out.println("You selected an UPPER CASE letter");
              break;
         case 'a':
         case 'b':
              System.out.println("You selected a LOWER CASE letter");
              break;
         default:
              System.out.println("That was an invalid entry.");
      };

      // Part 4: A common programming mistake is to accidently leave out a
      //         break statement. Instead of leaving the switch statement
      //         the program control falls into the next case.

      System.out.println();
      System.out.println("Simulate a missing break in the switch statement");

      char cC = 'B';
      switch ( cC ) {
         case 'A':
         case 'B':
              System.out.println("You selected an UPPER CASE letter");
         case 'a':
         case 'b':
              System.out.println("You selected a LOWER CASE letter");
              break;
         default:
              System.out.println("That was an invalid entry.");
      };

   }
}