Find the sum of the main diagonal elements of a matrix with C.

#include <stdio.h>

int main()
{
    int A[3][3];
    int row, col, sum = 0;

    /* Input elements in matrix from user */
    printf("Enter elements in matrix of 3 %dx%d: \n", 3, 3);
    for (row = 0; row < 3; row++)
    {
        for (col = 0; col < 3; col++)
        {
            scanf("%d", &A[row][col]);
        }
    }

    /* Find sum of main diagonal elements */
    for (row = 0; row < 3; row++)
    {
        sum = sum + A[row][row];
    }

    printf("\nSum of main diagonal elements = %d", sum);

    return 0;
}

Output

Enter elements in matrix of size 3x3 :
1 2 3
4 5 6
7 8 9

Sum of main diagonal elements = 15