error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException in jagged array loop

Question

A beginner in Java here. I'm making a jagged array program where the rows are 10 descending to 1 and they need to be from 0-9

expected output :

0  1  2  3  4  5  6  7  8  9 
1  2  3  4  5  6  7  8  9
2  3  4  5  6  7  8  9
3  4  5  6  7  8  9
4  5  6  7  8  9 
5  6  7  8  9
6  7  8  9
7  8  9
8  9
9

I have this

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 5 out of bounds for length 5
    at Compilations.JaggedArrLab.main(JaggedArrLab.java:23)

error that I have never encountered before so I don't really know what this means nor how to fix it.

Here is my code :

package Compilations;


public class JaggedArrLab {
   
    public static void main(String[] args) {
        int array[][] = new int [10][];
        //initializing rows from 10-1
        array [0] = new int [10];
        array [1] = new int [9];
        array [2] = new int [8];
        array [3] = new int [7];
        array [4] = new int [6];
        array [5] = new int [5];
        array [6] = new int [4];
        array [7] = new int [3];
        array [8] = new int [2];
        array [9] = new int [1];
        
         for (int i = 0; i<array.length; i++){
             for (int j=0; j<i + 1; j++){
                 array[i][j] = i + j;
             }
         }
         for (int i = 0; i<array.length;i++){
             for (int j=0; j<i + 1; j++)
               System.out.println(array[i][j] + "\t");
             
         }
         System.out.println();
    }
}

score 0 · Accepted Answer · answered Feb 19 '21 at 08:36

ArrayIndexOutOfBoundException is thrown when you try to access an element which isn't declared as part of your array. This usually happens when the loops boundary conditions are wrong.

Adding the code which works, please refer to it and check your loop conditions.

package Compilations;


public class JaggedArrLab {
   
    public static void main(String[] args) {
        int array[][] = new int [10][];
        //initializing rows from 10-1
        array [0] = new int [10];
        array [1] = new int [9];
        array [2] = new int [8];
        array [3] = new int [7];
        array [4] = new int [6];
        array [5] = new int [5];
        array [6] = new int [4];
        array [7] = new int [3];
        array [8] = new int [2];
        array [9] = new int [1];
        
         for (int i = 0; i< array.length ; i++){
             for (int j=0; j< array.length - i; j++){
                 array[i][j] = i + j;
             }
         }
         for (int i = 0;  i< array.length ;i++){
             for (int j=0; j< array.length - i ; j++)
               System.out.print(array[i][j] + "\t");
              System.out.println();
             
         }
         System.out.println();
    }
}

Output

0   1   2   3   4   5   6   7   8   9   
1   2   3   4   5   6   7   8   9   
2   3   4   5   6   7   8   9   
3   4   5   6   7   8   9   
4   5   6   7   8   9   
5   6   7   8   9   
6   7   8   9   
7   8   9   
8   9   
9

error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException in jagged array loop

1 Answers1