Using switch Structures

Submitted by GeePee on Wednesday, May 20, 2015 - 21:42.

The following is a Java Program using switch structures. In Java, switch, case, break and default are reserved words. In a switch structure, the expression is evaluated first. The value of expression is then used to perform the actions specified in the statements that follow the reserved word case. I will be using the JCreator IDE in developing the program. To start in this tutorial, first open the JCreator IDE, click new and paste the following code:

import java.util.*;
public class BreakStatementInSwitch
{
        static Scanner console = new Scanner(System.in);
        
        public static void main (String[] args)
        {
                int num;
                
                System.out.println("Enter an integer between 0 and 10: ");
                
                num = console.nextInt();
                System.out.println();
                
                System.out.println("The number you enter is " + num);
                
                switch (num)
                {
                        case 0:
                        case 1: System.out.print("Hello " );
                        case 2: System.out.print("there " );
                        case 3: System.out.print("I am " );
                        case 4: System.out.println("Dodgers " );
                                        break;
                        case 5: System.out.print("How " );
                        case 6:
                        case 7:
                        case 8: System.out.print("are you " );
                                        break;
                        case 9: break;
                        case 10: System.out.println("Have a nice day!" );               
                                        break;
                        default: System.out.println("Sorry the number is out of range!");
                        
                
                }
                        System.out.println("Out of the switch structure!");
                
        }
}


Sample Run 1:
Enter an integer between 0 and 10: 
1
The number you enter is 1
Hello there I am Dodgers 
Out of the switch structure!

Sample run 2:
Enter an integer between 0 and 10: 
3

The number you enter is 3
I am Dodgers 
Out of the switch structure!

Sample run 3:

Enter an integer between 0 and 10: 
4

The number you enter is 4
Dodgers 
Out of the switch structure!

Sample run 4:

Enter an integer between 0 and 10: 
5

The number you enter is 5
How are you Out of the switch structure!

Sample run 5:

Enter an integer between 0 and 10: 
7

The number you enter is 7
are you Out of the switch structure!

Sample run 6:

Enter an integer between 0 and 10: 
9

The number you enter is 9
Out of the switch structure!

Sample run 7:

Enter an integer between 0 and 10: 
10

The number you enter is 10
Have a nice day!
Out of the switch structure!

Sample run 8:

Enter an integer between 0 and 10: 
11

The number you enter is 11
Sorry the number is out of range!
Out of the switch structure!

A walk through of this program, using certain values of the switch expression, num, can help you understand how the break statement functions. If the value of num = 0, the value of the switch expression matches the case value . The first break appears break;, just before the case value of 5. When the value of the switch statement expression matches a case value, all statements execute until a break is encountered, and the program skips all case labels in between. If the value of num is 3, it matches the case value of 3 and the statements following this label execute until the break statement is encountered in break;. If the value of num is 9, it matches the case value of 9. In this situation, the action is empty, because only break statement case 9: break;, follows the case value of 9.

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