View Code of Problem 51

#include <cstdio>
#include <cstdlib>
using namespace std;
int a[30][30];  
int main()
{
    int n,i,j,sum=0;
    while(scanf("%d",&n)!=EOF){
    	sum = 0;                 
    	for(i=1;i<=n;i++)
    	{
        	for(j=1;j<=n;j++)
       		{
            	scanf("%d",&a[i][j]);
       		}
    	}
    	for(i=1;i<=n;i++)
    	{
        	for(j=1;j<=i;j++)
        	{
        		sum+=a[i][j];
        	}
    	}
    	printf("%d\n",sum); 
	}
    return 0;
}