How do we do sum of indexes in a 2D array

Question

I have a 2D array where rows = 3 and columns = 2. I want to get a sum of all the indices. Here is my array.

arr[][] = [1, 2], [3, 4], [5, 6]

• Row 1

  At index (0, 0) the sum of indexes becomes (0 + 0 = 0)

  At index (0, 1) the sum of indexes becomes (0 + 1 = 1)

• Row 2

  At index (1, 0) the sum of indexes becomes (1 + 0 = 1)

  At index (1,1) the sum of indexes becomes (1 + 1 = 2)

• Row 3

  At index (2, 0) the sum of indexes becomes (2 + 0 = 2)

  At index (2, 1) the sum of indexes becomes (2 + 1 = 3)

My expected output becomes

0 1 1 2 2 3

I am unable to find any resource, how to do this

Answer 1

You have to do sum of column and row using for loop or any other loop.

import java.util.*;
public class Main    
{    
    public static void main(String[] args) {    
        int rows, cols, sumIndex = 0;    
            
        int a[][] = {       
                        {1, 2},    
                        {3, 4},    
                        {5, 6}    
                    };
                    
        rows = a.length;    
        cols = a[0].length;    
                    
        for(int i = 0; i < rows; i++){    
            for(int j = 0; j < cols; j++){    
              sumIndex = i + j;
              System.out.print(sumIndex + " ");
            }    
        }   
    }    
} 

Answer 2

Another quick example:

import java.util.*;
class Main {

  public static void main(String[] args) {       
    int[][] arr = new int[3][2];
    for(int row=0; row<arr.length; row++) {
      for(int col=0; col<arr[row].length; col++) {
        arr[row][col] = row + col;
      }
    }

    for(int[] row : arr) {
      System.out.println(Arrays.toString(row));
    }
  }
 
}

Output:

[0, 1]
[1, 2]
[2, 3]