View Code of Problem 51

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