C++ Programming using iostream and namespace std

Write a function diagonalSum that takes in a 2-D array of int type and their row sizes and returns sum of main diagonal(left diagonal) elements. (Assume column size is always 3)

int diagonalSum(int arr[][3], int row)

Example:

arr[3][3]= {{1, 4, 6}, {7, 23, 3}, {5, 15, 25}}

diagonal sum = 1+23+25

return value: 49

arr[3][3]= {{1, 4, -6}, {17, -23, 3}, {-5, 15, 5}}

diagonal sum = 1-23+5

return value: -17

arr[3][3] = {{-1, 4, 6}, {17, -3, 3}, {5, 15, 4}}

return value: 0