Hdu-2156-分数矩阵 [水题]

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <stack>
using namespace std;
int main(void)
{
int n;
while (scanf("%d", &n))
{
if (n==0)
break;
double s=0,ss=0;
for (int i = 1; i <= n; i++)
{
ss = ss+1.0/i;
s = s + ss;
}
printf("%.2f\n",s*2-n);
}
return 0;
}