Java ArrayIndexOutOfBounds

Question

Currently working on a student project. I want to figure out the highest number and sort it by bubble sort, the number is parsed from a JLabel, but I get this error everytime. Here is a code snippet:

    JLabel[] wuerfelsummen = new JLabel[7];
    wuerfelsummen[0] = player1_wuerfelsumme;
    wuerfelsummen[1] = player2_wuerfelsumme;
    wuerfelsummen[2] = player3_wuerfelsumme;
    wuerfelsummen[3] = player4_wuerfelsumme;
    wuerfelsummen[4] = player5_wuerfelsumme;
    wuerfelsummen[5] = player6_wuerfelsumme;

public int ermittleGewinner(JLabel[] w)
{
    int temp;
    int[] zahlen = new int[w.length];
    for(int i=0; i<=zahlen.length; i++)
    {
        if(w[i].getText() == null)
        {
            zahlen[i] = 99999999;
        }
        else
        {
            zahlen[i] = Integer.parseInt(w[i].getText());
        }
    }

    for(int i=1; i<zahlen.length; i++) 
    {
        for(int j=0; j<zahlen.length-i; j++) 
        {
            if(zahlen[j]>zahlen[j+1]) 
            {
                temp=zahlen[j];
                zahlen[j]=zahlen[j+1];
                zahlen[j+1]=temp;
            }

        }
    }

Dragondraikk · Accepted Answer · 2015-06-02 15:59:23Z

3

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

This is incorrect, as arrays are 0-indexed, meaning they reach from 0 to length-1.

Change it to

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

Interestingly enough, your other loops avoid this pitfall, although you will still have to be careful about the j+1 later on. Make sure that this can never be >= zahlen.length.

You could simply initialize j with 1 instead of 0 and then replace all occurences of j with j-1 and j+1 with j

edited Jun 2, 2015 at 15:59

answered Jun 2, 2015 at 15:52

Dragondraikk

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1 Comment

Dragondraikk Over a year ago

As @GriffeyDog pointed out, you need to be careful about j+1 in your other loop. You have to ensure that it will never be >= zahlen.length

GregH · Accepted Answer · 2015-06-02 15:55:11Z

0

change "i<=zahlen.length" in your for loop to "i < zahlen.length".

remember arrays are 0 indexed so you are trying to access an element one index outside of how large your array is with the "<=" method you are currently using

The second loop should start at i=0 instead of i=1. By using i=1, you are again going to try to access one element past the size of your array

answered Jun 2, 2015 at 15:55

GregH

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Comments

hagrawal7777 · Accepted Answer · 2015-06-02 15:58:18Z

0

ArrayIndexOutOfBounds expcetion comes when code tried to access an element of an array which is not present. In your code, since you are FOR looping one extra time for(int i=0; i<=zahlen.length; i++), you are getting this exception. Keep FOR loop as for(int i=0; i<zahlen.length; i++)

You have not to just check for zahlen[i] but also for w[i] because you are looping on length of zahlen and it may so happen that w is of lesser length then zahlen.

answered Jun 2, 2015 at 15:58

hagrawal7777

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