View Code of Problem 51

#include<stdio.h>
#include<math.h>
#include<string.h>
int main() {
	int n;
	int a[100][100];
	int sum;
	scanf("%d", &n);
	int i, j;
	for (i = 0; i < n; i++) {
		for (j = 0; j < n; j++) {
			scanf("%d", &a[i][j]);
		}
	}
	sum = 0;
	for (i = 0; i < n; i++) {
		for (j = 0; j <= i; j++) {
			sum += a[i][j];
		}
	}
	printf("%d\n", sum);
	return 0;
}