Thread: Help in looping

So, here's my code. I have a runtime error and I think there's a problem in the loop in it but I can't figure it out.

 import java.util.Scanner;
    public class BankSystem
   {
       public static void main(String[] args)
      {
         double acc=1000,d,w;
         int exit, selector;
         char enter;	
         Scanner keyboard = new Scanner(System.in);
         System.out.println("To use the bank system, select 'y' or any other letter to exit.");
         enter = keyboard.nextLine().charAt(0);
         while (enter == 'y')
         {
            System.out.println("Enter one of the following options:");
            System.out.println(" * '1' for account balance.");
            System.out.println(" * '2' for withdraw.");
            System.out.println(" * '3' for deposit.");
            selector = keyboard.nextInt();
            switch (selector)
            {
               case 1:
                  System.out.println("Your balance is: "+acc);
                  break;
               case 2:
                  System.out.println("Enter the amount to withdraw.");
                  w = keyboard.nextDouble();
                  if (w<=0 || w>acc)
                     System.out.println("Wrong input.");
                  else
                     acc=acc-w;
                  System.out.println("The selected amount has been withdrawed from your account successfully.");
                  break;
               case 3:
                  System.out.println("Enter the amount to deposit.");
                  d=keyboard.nextDouble();
                  while (d<=0)
                  {
                     System.out.println("Wrong input.");
                     System.out.println("Enter the right amount.");
                     d = keyboard.nextDouble();
                  }
                  acc=acc+d;
                  System.out.println("The selected amount has been deposited into your account successfully.");
                  break;
               default:
                  System.out.println("Wrong selection.");
            }
            System.out.println("To continue using the system, select 'y' or any other letter to exit.");
            enter = keyboard.nextLine().charAt(0);
         }
         System.out.println("System is shutting down...");
      }
   }

Any help or hints on how to correct my error would be great. Thanks.

Whats the runtime error?

Originally Posted by Freaky Chris

Whats the runtime error?

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 0
at java.lang.String.charAt(String.java:686)
at BankSystem.main(BankSystem.java:49)

Clear the input buffer before reading the nextLine, nexInt leaves a \n character in the buffer. Meaning that when you do nextLine no input is read from the user and an empty String is returned thus, when you try to get the letter at 0 you get the exception because the String doesn't have a length of 1, it has a length of 0.

Chris

Thanks guys, it worked and now I understand what was wrong.
Best wishes to all.