View Code of Problem 51

#include<stdio.h>
int main()
{
	int n,a[20][20],i,j,s=0;
	scanf("%d",&n);
	for(i=0;i<n;i++)
	for(j=0;j<n;j++)
	scanf("%d",&a[i][j]);
	for(i=0;i<n;i++)
	for(j=0;j<=i;j++)
	s=s+a[i][j];
	printf("%d",s);
	
}