public class Diagonal2DArray { public static void main(String[] args) { System.out.println("Welcome to Sum of Diagonal in 2D Array:\n"); int[][] numArr = ArrayUtility.input2DArray(); long sumOfDiagonal = sumOfDiagonal(numArr); System.out.println("Sum of Diagonal is : "+sumOfDiagonal); } public static long sumOfDiagonal(int[][] numArr ){ long leftSum = sumOfLeftDiagnoal(numArr); long rightSum = sumOfRightDiagnoal(numArr); long sum = leftSum + rightSum ; if(numArr.length % 2 != 0){ int ind = numArr.length / 2; sum -= numArr[ind][ind]; } return sum; } public static long sumOfLeftDiagnoal(int[][] numArr ){ long sum = 0 ; int i = 0; while(i < numArr.length){ sum = sum + numArr[i][i]; i++; } return sum; } public static long sumOfRightDiagnoal(int[][] numArr ){ long sum = 0 ; int i = 0; while(i < numArr.length){ int col = numArr.length - 1 - i ; sum = sum + numArr[i][col]; i++; } return sum; } }