Diagonal Summation

11 2 4
4 5 6
10 8 -12

Explanation




The primary diagonal is: 
11
      5
            -12

Sum across the primary diagonal: 11 + 5 - 12 = 4

It may be done 2 ways:

First way:

    int total = 0;

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

    {

        total += a[row][row];

    }




Second way:

  //Logic to calculate sum of diagonal1

           int sumOfDiagonal1=0;

           for (int i = 0, j =0; i< rows && j < columns; i++, j++) {

                  sumOfDiagonal1= sumOfDiagonal1 + matrix[i][j];

                  

           }


Resource Link:

https://www.hackerrank.com/challenges/diagonal-difference

http://www.javamadesoeasy.com/2015/02/find-sum-of-both-diagonals-in-matrix.html