Java OutofBoundException in Array

Question

I got this error. Though it may be very basic. I have declared array of length 3. Why does it still show an OutofBoundException error ?

    public static void main(String[] args) {
            int i;
            String[] arr = new String[3];
            Scanner input = new Scanner(System.in);
            System.out.println("Please enter the name");
            for (i = 0; i < 3; i++) {
                arr[i] = input.nextLine();
            }
            System.out.println(arr[i]);
        }
   Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
        at arraysPractice.Arr2.main(Arr2.java:21)

the index is from 0, so when the length of array is 3 then index of them is:0 ,1,2 — nail fei, Dec 29 '16 at 08:49

score 3 · Answer 1 · answered Dec 29 '16 at 08:48

3

It's because after completion of for loop, your i will be 3. Which is outOfBound because your array size is 3 only.

so print

System.out.println(arr[i-1]);

if you want to print last element.

NOTE

To avoid this type of errors, try using arr[arr.lenght - 1] to print last element.

answered Dec 29 '16 at 08:48

Kaushal28

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you can accept the answer by pressing small right below voting button, if it solved your problem. :) @user2863083 – Kaushal28 Dec 29 '16 at 09:55

score 0 · Answer 2 · answered Dec 29 '16 at 08:49

0

The loop is terminated with i having the value of 3. You then try to print arr[i], which won't work, since it only has the indexes 0, 1 and 2.

I'm guessing you meant to have the System.out.println statement inside the loop instead of after it?

answered Dec 29 '16 at 08:49

Mureinik

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score 0 · Answer 3 · answered Dec 29 '16 at 10:42

first iteration). I=0 and 0<3 so it goes into for loop and after that I++ so I=1.
second iteration).I=1 and 1<3 so it goes into for loop and after that I++ so I=2.
third iteration)I=2 and 2<3 so it goes into for loop and after that I++ so I=3
fourth iteration)I=3 and 3<3(false) it will exit loop and after that u are you are trying to print. System.out.println(arr[i]);where I=3. and your array size=3(means max position can be 2 and remaining positions are (0,1,2)) so it is index out of bound as you want to check array with index 3 but array max index is 2.

So QUICK fix put System.out.println(arr[i]); in for loop.

Java OutofBoundException in Array

3 Answers3