多项式求和 HDU - 2011

2
1 2

1.00
0.50

#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstdio>
using namespace std;

int main()
{
	int m = 0;
	cin >> m;
	double ans = 0;
	int a;
	while (m--)
	{
		cin >> a;
		double temp=0.00;
		for (int i = 1; i <= a; i += 2)
		{
			//temp = 1 / i;这样得到的结果是0！！！！！ans永远是1.00
			temp = (double)1 / i;
			ans += temp;
			//cout << ans << "   " << i << endl;
		}
		for (int i = 2; i <= a; i += 2)
		{
			temp = (double)1 / i;
			ans -= temp;
		}

		printf("%.2lf\n", ans);
		ans = 0;
	}
	return 0;
}