How do i get rid of this java.lang.ArrayIndexOutOfBoundsException error?

Question

        String[][] tArray=new String[2][4];

    for (int row=0; row<=2;row++){

        for (int col=0,count=0;col<=4;col++ ,count++){
            Scanner input=new Scanner(System.in);
            System.out.print("Please Enter the name " +count+ ":");
            tArray[row][col]=input.next();
        }

    }

    for (int row=0; row<=2;row++){

        for (int col=0;col<=4;col++){
            System.out.println(tArray[row][col]);
        }

    }

Error : -

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4 at array.testArray.main(testArray.java:15)

Ankit Rustagi · Accepted Answer · 2013-11-16 13:19:06Z

2

The problem is

        for (int col=0,count=0;col<=4;col++ ,count++){

you can only go upto 3 and not 4, as indices start from 0. Use this

        for (int col=0,count=0;col<4;col++ ,count++){

Same here

for (int row=0; row<=2;row++){   // incorrect

do this

for (int row=0; row<2;row++){

answered Nov 16, 2013 at 13:19

Ankit Rustagi

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1 Comment

Ankit Rustagi Over a year ago

Thanks! added this to the answer.

kviiri · Accepted Answer · 2013-11-16 13:23:16Z

Remember that Java's indexes start from zero and end at length - 1! You're trying to find three "rows" of the array where there are only two:

for (int row=0; row<=2;row++){ //0, 1, 2 - that's three options even though the array's size is only 2

and likewise five columns where there are only four:

for (int col=0,count=0;col<=4;col++ ,count++){ //0, 1, 2, 3, 4 - that makes five

Using < in place of <= should fix this particular issue, although I would also recommend using the length attribute of the array to find out the actual size of the array each time instead of hard-coding it. It's safer from human error and works even if you change the size of your array:

for (int row=0; row < tArray.length; row++){

and

for (int col=0,count=0;col < tArray[row].length; col++ ,count++){

Finally, even though this is a bit off-topic, col and count seem to always have the same value so I'd suggest removing either.

Sudhakar Tillapudi · Accepted Answer · 2013-11-16 13:38:53Z

0

Reason: You are iterating the Loop more than the Items Length.

problem is here:

String[][] tArray=new String[2][4];//means 2 rows and 4 columns

for (int row=0; row<=2;row++)//row 0 to 2 => 0,1,2 iterates 3 times
{

    for (int col=0,count=0;col<=4;col++ ,count++)//column 0 to 4 => 0,1,2,3,4 iterates 5 times
    {
    //code   
    }

}

for (int row=0; row<=2;row++)//row 0 to 2 => 0,1,2 iterates 3 times
{

    for (int col=0;col<=4;col++)//column 0 to 4 => iterates 0,1,2,3,4
    {
   //code
    }

}

Solution:

 String[][] tArray=new String[2][4];

    for (int row=0; row<2;row++){

        for (int col=0,count=0;col<4;col++ ,count++){
            Scanner input=new Scanner(System.in);
            System.out.print("Please Enter the name " +count+ ":");
            tArray[row][col]=input.next();
        }

    }

    for (int row=0; row<2;row++){

        for (int col=0;col<4;col++){
            System.out.println(tArray[row][col]);
        }

    }

answered Nov 16, 2013 at 13:38

Sudhakar Tillapudi

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3 Comments

k9yosh Over a year ago

Thank you very much. I did the changes. but it displays the same error, Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4 at array.testArray.main(testArray.java:23) it displays upto 4 elements. i think it's something to do with the last For loop. Can u please help me with that?

Sudhakar Tillapudi Over a year ago

sure i will help you please edit your question with latest code

k9yosh Over a year ago

i got it right.. :p it was just a silly mistake.. thank you very much.. owe u big time.. i was having a wrong idea about Array rows & columns And thank you guys for helping me out.

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