Getting exception in thread "main" java.util.InputMismatchException

Question

I am trying to take input one by one and then trying to perform operations over them. Following my code.

   import java.util.Scanner;

    public class PlayerRoster {
       public static void main(String[] args) {
          Scanner scnr = new Scanner(System.in);
      
          final int LENGTH = 5;
          final char quit = 'q';
          char uin = 'z';
          int jersey = 0;
          int chng = 0;
      
          int[] number = new int[LENGTH];
          int[] rating = new int[LENGTH];
      
          for(int i = 0; i < LENGTH; i++){
             System.out.println("Enter player "+(i+1)+"'s jersey number:");
             number[i] = scnr.nextInt();
             System.out.println("Enter player "+(i+1)+"'s rating:\n");
             rating[i] = scnr.nextInt();
          }
          for(int i = 0; i < LENGTH; i++){
             if (i == 0)
                System.out.println("ROSTER");
      
                 System.out.println("Player " + (i + 1) + " -- Jersey number: " + (number[i]) + ", Rating: " + (rating[i]));
             if (i == 4)
                System.out.println("");
      
          }
          while (uin != quit){
         
             System.out.println("MENU");
             System.out.println("u - Update player rating");
             System.out.println("a - Output players above a rating");
             System.out.println("r - Replace player");
             System.out.println("o - Output roster");
             System.out.println("q - Quit\n");
       
             System.out.println("Choose an option:");
              uin = scnr.next().charAt(0);
      
             if (uin == 'o')
                for(int i = 0; i < LENGTH; i++){
                   if (i == 0)
                      System.out.println("ROSTER");
                      System.out.println("Player " + (i + 1) + " -- Jersey number: " + (number[i]) + ", Rating: " + (rating[i]));
                   if (i == 4)
                      System.out.println("");
                }
         
         
             if (uin == 'u')
                System.out.println("Enter a jersey number: ");
                   chng = scnr.nextInt();
         
          }  
       }
    }

I am not currently focused on logic as I am not able to take the input, as I am getting Exception in thread "main" java.util.InputMismatchException When simply trying to get more user input.

My Inputs are: 20 5 30 2 50 4 60 8 93 9 u 20 q

I have tried everything from char to normal Strings. It feels as if the scanner just isn't working or something.

    Exception in thread "main" java.util.NoSuchElementException
        at java.base/java.util.Scanner.throwFor(Scanner.java:937)
        at java.base/java.util.Scanner.next(Scanner.java:1594)
        at java.base/java.util.Scanner.nextInt(Scanner.java:2258)
        at java.base/java.util.Scanner.nextInt(Scanner.java:2212)
        at PlayerRoster.main(PlayerRoster.java:55)

on which line does it happen? it might be because you are mixing up nextInt() and next() calls. the nextInt() doesn't consume the enter — Stultuske, Nov 16 '20 at 07:25
you mean, you added the stacktrace (or part of it)? you're aware that that isn't code, right? — Stultuske, Nov 16 '20 at 07:29
@Stultuske yes im aware its not code. I'm just saying that because i frustratingly had to indent it as code to publish the damn stacktrace. — holdthemayo7, Nov 16 '20 at 07:30
Cannot reproduce the problem. With the given input the program does not fail with an exception. — Milgo, Nov 16 '20 at 07:32
@Milgo the errors im getting are real. So what could be the issue then? I've been stuck on this for tooooo long now. — holdthemayo7, Nov 16 '20 at 07:36

Shubham Chopra · Accepted Answer · 2020-11-16T07:45:51.680

1

The issue is the code block

 if (uin == 'u')
        System.out.println("Enter a jersey number: ");
           chng = scnr.nextInt();

Since you want the jersey number only in case when user gives input as 'u' your chng = scnr.nextInt(); should be inside the if block. In your case even if user gives input as 'q', it is still expecting more input from the user, and probably you are just giving blank space in that case giving you InputMisMatchException.

To fix it please update code to

if (uin == 'u')
{
     System.out.println("Enter a jersey number: ");
     chng = scnr.nextInt();
}

So now if you give input as 'q' your loop stops executing which is the expected output.

edited Nov 16 '20 at 07:45

answered Nov 16 '20 at 07:38

Shubham Chopra

1,678
17
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I no longer have errors after changing my code to this. Thanks a lot! I had no idea I needed to bracket if statements ever. – holdthemayo7 Nov 16 '20 at 07:43
1

You need to add brackets to if statement if you want more than 1 statement to be included inside the if block, otherwise its optional. – Shubham Chopra Nov 16 '20 at 07:44
@holdthemayo7 You've got the same problem in the lines with `System.out.println("Player "`, as well. It doesn't cause exceptions there, it just always prints this line. – Hulk Nov 16 '20 at 07:46

Getting exception in thread "main" java.util.InputMismatchException

1 Answers1