Make an Array Sorter

Question

I am trying to make an array sorter. But I get an error:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 7

I don't know how to fix it. If I delete the line with the arrow then the code works, but then it doesn't swap. What did I do wrong?

Thanks for your help!

public class Main {

    public static void main(String[] args) {
        int[] list = {5, 3, 7, 2, 4, 8};

        for (int i = 0; i < list.length; i = i + 2) {
            if (i != list.length - 1) {

                if (list[i] > list[i + 1]) {

                    int leftNumber = list[i];
                    int rightNumber = list[i + 1];

                    int src = i;
                    int temp = list[i];

                    list[i] = list[i + 1];
                    //--> list[i + 1] = list[temp];

                    System.out.println(leftNumber + " : " + rightNumber);
                    System.out.println(i + " : " + (i + 1));

                    System.out.println(Arrays.toString(list));


                } else {
                    System.out.println("Good!");
                }
            }
        }


    }



}

`i == list.length - 1 -> 5 + 1 = 6` That's not 7... Or am I thinking wrong? — Bastiaan, Mar 02 '18 at 14:42
@Bastiaan So, if `list.length == 6`, what do you think `list[6]` will give you? — BackSlash, Mar 02 '18 at 14:42
`list[i +1]` is one problem, but the current problem is that you try to access `list[temp]` with `temp` beeing the value of on element of your `list[i]`. Obviosuly there is no guarantee that a list that contains the number 7 actually has an element with the index 7. What are you trying to do in that line? — OH GOD SPIDERS, Mar 02 '18 at 14:43
I am trying to swap index 0 with index 1 because 5 is bigger than 3. @OHGODSPIDERS — Bastiaan, Mar 02 '18 at 14:44

score 2 · Answer 1 · answered Mar 02 '18 at 14:42

2

temp is not an array index: you assigned it list[i], which is an array element.

answered Mar 02 '18 at 14:42

Davis Herring

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score 2 · Answer 2 · answered Mar 02 '18 at 14:43

2

int temp = list[i]; and list[i + 1] = list[temp]; are the lines which cause the problem.

temp could be more than size of the list, how could you access list[temp], you may want to replace that with list[i+1] = temp

answered Mar 02 '18 at 14:43

SomeDude

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Abhijit Pritam Dutta · Answer 3 · 2018-03-02T14:56:32.753

0

You problem is with list[temp];. Here it will crash when temp value is larger than your array size. You need to correct your code like below:-

list[i + 1] = leftNumber;
list[i ] = rightNumber;

It will still crash in the if condition hence change your for loop like below:

 for (int i = 0; i < (list.length - 1); i = i + 2)

As you are swapping the value here which you stored already hence no need for below lines of codes at all:-

/*
int src = i;
int temp = list[i];

list[i] = list[i + 1];
--> list[i + 1] = list[temp];
 */

All the above lines are useless.

edited Mar 02 '18 at 14:56

answered Mar 02 '18 at 14:45

Abhijit Pritam Dutta

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`list[i + 1]` is an issue too, as `i + 1` goes out of bounds when `i == list.length - 1` – BackSlash Mar 02 '18 at 14:46
@BackSlash, Yes true in that condition it will crash here `if (list[i] > list[i + 1]) ` – Abhijit Pritam Dutta Mar 02 '18 at 14:49

Make an Array Sorter

3 Answers3