View Code of Problem 51

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <math.h>

int a[15][15];

int main()
{
    int n;
    while (scanf("%d", &n) != EOF) {
        int sum = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                scanf("%d", &a[i][j]);
                if (j <= i) {
                    sum += a[i][j];
                }
            }
        }
        
        printf("%d\n", sum);
    }
}