View Code of Problem 51

#include <stdio.h>
#include <math.h>
int main()
{
    int n;
    scanf("%d",&n);
    int a[100][100];
    for (int i=0;i<n;i++)
    {
        for (int j=0;j<n;j++)
        {
            scanf("%d",&a[i][j]);
        }
    }
    int sum = 0;
    for (int i=0;i<n;i++)
    {
        for (int j=0;j<=i;j++)
        {
            sum = sum + a[i][j];
        }
    }
    printf("%d\n",sum);
}