Secondary Diagonal Sum

Easy 2D Arrays (Matrices)
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Problem Statement

Write a C program to find the sum of elements on the secondary (anti) diagonal of a square matrix N x N.

Input Format

First line: N. Then N lines of N integers.

Output Format

Print the secondary diagonal sum.

Constraints

1 <= N <= 10

Sample Input

3
1 2 3
4 5 6
7 8 9

Sample Output

15

Explanation

Anti-diagonal elements are 3, 5, and 7. Sum = 3 + 5 + 7 = 15.

Starter Code

#include <stdio.h>

int main() {
    int n;
    if (scanf("%d", &n) == 1) {
        int a[n][n];
        for(int i=0; i<n; i++) for(int j=0; j<n; j++) scanf("%d", &a[i][j]);
        // Write your code here
    }
    return 0;
}

Limits

  • Time Limit: 1s
  • Memory Limit: 256MB

Embedded C Programming

Updated: March 15, 2026
Intermediate

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