View Code of Problem 51

#include<stdio.h>

int main()
{
	int n;
	int matrix[11][11];
	int sum = 0;
	
	scanf("%d", &n);
	for(int i = 0; i < n; i++)
		for(int j = 0; j < n; j++)
		{
			scanf("%d", &matrix[i][j]);
			if(j < i+1)
				sum += matrix[i][j];
		}
	printf("%d", sum);
	return 0;
}