View Code of Problem 51

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;


int sumstr(int a[100][100], int n) {
	int sum = 0;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= i; j++) {
			sum += a[i][j];
		}
	}
	return sum;
}
int main() {
	int str[100][100];
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			cin >> str[i][j];
		}
	}
	int sum = sumstr(str, n);
	cout << sum;
	return 0;
}