how to fix "Exception in thread "main" java.util.NoSuchElementException"?

Question

I'm trying to print pairs of elements whose sum is matched with the input. But it shows an error in the line int size=s.nextInt();.

how can I fix this?

import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner s=new Scanner(System.in);
    System.out.println("Enter the size of the array");
    int size=s.nextInt();
    int arr[]=new int[size];
    getElements(arr,size);
    System.out.println("Enter the sum data");
    int sum=s.nextInt();
    printPairs(arr,sum);
  }
  static void getElements(int a[],int sizee){
    //have the logic for accepting input numbers
    Scanner s=new Scanner(System.in);
    System.out.println("Enter "+sizee+" elements");

    for(int i=0;i<a.length;i++){

      a[i]=s.nextInt();
      }

  }
  static void printPairs(int a[],int data){
    //have the logic for printing pair information 
    for (int i=0;i<a.length;i++){
       int first = a[i];
      for (int j=i+1;j<a.length;j++){
        int second = a[j];
        if(first+second == data)
        System.out.println("("+first+", "+second+")");
      }
    }
  }
}

Exception:

Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Scanner.java:862)
    at java.util.Scanner.next(Scanner.java:1485)
    at java.util.Scanner.nextInt(Scanner.java:2117)
    at java.util.Scanner.nextInt(Scanner.java:2076)
    at Main.main(Main.java:7)

Input: this is the expected input

Please, show input and consider remove `System.out.println` before `s.nextInt()` — Dmytro Chasovskyi, Jul 19 '19 at 13:13
Are two `Scanner`s necessary? You could just use one and pass it as a parameter to `getElements` — Maxime Launois, Jul 19 '19 at 13:13

score 0 · Answer 1 · answered Jul 19 '19 at 13:15

Making another scanner is problematic (Not sure if scanner buffers, but if it does, this code wouldn't work). Pass it along or create one as a field in your class.

Other than that, there's nothing inherently wrong with this code: The error is what you get because that's what's happening: You are passing as input, say:

2 1 3

and then ending the input entirely (for example by hitting a certain keycombo, or you're providing the input via file, i.e. with java -cp . com.foo.YourApp <inputs.txt and the file ends there. Your app would need another number (representing the sum) in this example.

how to fix "Exception in thread "main" java.util.NoSuchElementException"?

1 Answers1