Matrix Diagonals Sum ID:2666

You are given a square matrix of size N×N. Calculate the sum of the integers present in the two main diagonals.

Input Format:
The first line will contain the value of N.
The next N lines will contain the N values separated by one or more spaces.

Output Format:
The sum of the integers present in the two main diagonals.

Boundary Conditions:
2 <= N <= 20

Example Input/Output 1:
Input:
2
10 9
4  22

Output:
45

Explanation:
The sum is = 10+22+9+4 = 45

Example Input/Output 2:
Input:
3
5 10 11
79 6 12
9 21 45

Output:
76

Explanation:
The sum is = 5+6+45+11+9 = 76.
As 6 is common for both the diagonals it must be counted only once when finding the sum.

Program in C:

#include<stdio.h>
#include <stdlib.h>

int main()
{
int n,arr[20][20];
scanf("%d",&n);
int sum=0;
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
scanf("%d",&arr[i][j]);
if(i==j)
sum=sum+arr[i][j];
else if(i+j==(n-1))
sum=sum+arr[i][j];
}
}
printf("%d",sum);

}