View Code of Problem 51

#include <stdio.h>
int main()
{
	int n,i,j;
	int a[9][9];
	scanf("%d", &n);
	for (i = 0; i < n; i++)
		for (j = 0; j < n; j++)
			scanf("%d", &a[i][j]);
	int sum = 0;
	for (i = 0; i < n; i++)
		for (j = 0; j < i + 1; j++)
			sum += a[i][j];
	printf("%d\n", sum);
	return 0;
}