View Code of Problem 51

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