Thread: How do I loop a switch Statement?

How do I loop a switch Statement?
I need to loop it so that when a user inputs a 1, 2, 3, or anything other than a 4 it restarts, and when the user types in a 4 the program terminates.

import javax.swing.JOptionPane ;
public class Input123
{
public static void main(String[] args)
{
int n;
n = Integer.parseInt(JOptionPane.showInputDialog(null,
"Enter a 1, 2, 3, or 4" )) ;
{
switch(n)
{
case 1:
case 2:
case 3:
System.out.println("Good Job!") ;
break ;
case 4:
System.out.println("Pragram Terminated") ;
break ;
default:
System.out.println("No such Parameter") ;
}
}
}

What you can do is place your switch inside a while loop => while(flag). Then inside the case 4 set the flag to false.

Originally Posted by Junky

What you can do is place your switch inside a while loop => while(flag). Then inside the case 4 set the flag to false.

Can you elaborate?

Use a boolean.

boolean foo = true;
while(foo) {
    //stuff
    if( x == 4) {
        foo = false;
    }
}

Above example uses an if but you can easily apply it to a switch

Originally Posted by Junky

Use a boolean.

boolean foo = true;
while(foo) {
    //stuff
    if( x == 4) {
        foo = false;
    }
}

Above example uses an if but you can easily apply it to a switch

It's compiles with no syntax errors, but it's still givng me an infinite loop where when I put in a 1, 2, 3, or any number other not 4 it outputs either "Good Job!" or "Parameter Error". So I probally have it wrong somewhere.

   import javax.swing.JOptionPane ;
   public class Input123
   {
      public static void main(String[] args)
      {     
         int n;
         n = Integer.parseInt(JOptionPane.showInputDialog(null,
               "Enter a 1, 2, 3, or 4" )) ;
         {
            boolean loop = true;
            while(loop) 
            { 
               switch(n)
               {
                  default:
                     System.out.println("Parameter Error") ;
                     break ;
                  case 1:
                     System.out.println("Good Job!") ;
                     break;
                  case 2:
                     System.out.println("Good Job!") ;
                     break;
                  case 3:
                     System.out.println("Good Job!") ;
                     break ;
                  case 4:
                     System.out.println("Pragram Terminated") ;
                     break ;
               }        
               if(n == 4) 
               {
                  loop = false;
               }
            }
         }
      }
   }

Yea he's right. You definitely need the input inside the while loop or its going to only ask once and keeping going with that same input forever.

package com.company.project;

import java.util.Scanner;

public class application {

public static void main(String[] args) {

Scanner scanner = new Scanner(System.in);
boolean runAgain = false;
boolean exitloop = false;

do {

System.out.println("Enter the command here, valid values are stop, start, to exit program type 'exit' : ");
String input = scanner.nextLine();

switch (input) {

case "start":

System.out.println("System has been started");
break;

case "stop":

System.out.println("system has been stopped");
break;

case "exit":
System.out.println("system has been stopped");
exitloop = true;
break;

default:

System.out.println("Command not recognized");
runAgain = true;

}

if (exitloop)
break;

} while (runAgain);

scanner.close();

}

}

Hi Arkeshen,

Here is a solution that I could work out, please let me know if I did not understand the requirements properly or if anything is not clear:

import javax.swing.JOptionPane ;
 
public class Input123 {
    public static void main(String[] args) {
        int n;
        n = Integer.parseInt(JOptionPane.showInputDialog(null,
                "Enter a 1, 2, 3, or 4"));
        {
            switch (n) {
                case 1:
                case 2:
                case 3:
                    System.out.println("Program restart"); //<---- program will restart if user enters 1, 2 or 3
                    //Here you need to replace the print statement with the actual code that will restart your program or do what you want to do
                case 4:
                    System.exit(0); //<----- program will terminate if user enters 4
                default:
                    System.out.println("No such Parameter"); //<----- if user enters anything other then 1, 2, 3 or 4 it prints "No such Parameter"
            }
        }
    }
}

Regards
Alin