Unable to print array 0th element

Question

Sir i am trying to print array's 0th element but i can't. Here is my code

import java.util.Scanner;
public class prog3
{
    public static void main (String[] args){
        Scanner input = new Scanner(System.in);
        int size = input.nextInt();
        String arr[] = new String[size];

        for (int i=0; i<size; i++){
            arr[i]= input.nextLine();
        }

        System.out.print(arr[0]);
    }
}

when i am trying to print arr[0] its return blank but when i print arr[1] it returns the 0th element value. would you please help me to find my error.

Sir i am new in java.Would you please explain the reason ? – Arka Bhattacharjee Dec 11 '13 at 13:19 — Arka Bhattacharjee, Dec 11 '13 at 13:19
see my edited answer for more information. – kai Dec 11 '13 at 13:23 — kai, Dec 11 '13 at 13:23

kai · Answer 1 · 2013-12-11T13:23:57.860

5

Change

arr[i]= input.nextLine();

to

arr[i]= input.next();

and it works. this is because nextLine() reads a whitespace and then it looks like arr[0] is empty. You can see this, because if the size is 3 you can input only two times. See http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html for more information about scanner :)

edited Dec 11 '13 at 13:23

answered Dec 11 '13 at 13:12

kai

6,219
16
37

Why does that work. Please explain your answer :) – Bart Dec 11 '13 at 13:13
Yes its working . Thank you so much .. would you please explain why nextLine() is not working – Arka Bhattacharjee Dec 11 '13 at 13:14
Are you sure he doesn't want to read lines containing ws? Since this would tokenize input with spaces, for example. – vikingsteve Dec 11 '13 at 13:16

score 2 · Accepted Answer · answered Dec 11 '13 at 13:14

2

Try this mate:

    input.nextLine();   // gobble the newline
    for (int i = 0; i < size; i++) {
        arr[i] = input.nextLine();
    }

answered Dec 11 '13 at 13:14

vikingsteve

34,284
19
101
142

the `nextLine()` method is a bit quirky, since there was a newline "hanging" after `nextInt()`. If you gobble it up, things should then work as you expect. – vikingsteve Dec 11 '13 at 13:17

score 2 · Answer 3 · edited May 23 '17 at 11:51

Corrected code: Include input.nextLine(); after input.nextInt()

import java.util.Scanner;
public class prog3{
  public static void main (String[] args){
    Scanner input = new Scanner(System.in);
    int size = input.nextInt();
    input.nextLine();
    String arr[] = new String[size];
    for (int i=0; i<size; i++){
    arr[i]= input.nextLine();
    }
         System.out.print(arr[0]);
  }

}

Input :

2
45
95

Output

Explanation:

The problem is with the input.nextInt() command it only reads the int value. So when you continue reading with input.nextLine() you receive the "\n" Enter key. So to skip this you have to add the input.nextLine(). Scanner issue when using nextLine after nextXXX

Unable to print array 0th element

3 Answers3