#include <iostream>
#include <iomanip>
using namespace std;
double SUM(int x)
{
if(x == 1) return 1;
else
{
int j, a = 1;
double sum = 0.0;
for(j = 0; j < x; ++j)
{
sum = sum + a*(1.0/(j+1));
a *= -1;
}
return sum;
}
}
int main()
{
int m, n;
int i, x;
while(cin >> m)
{
for(i = 0; i < m; ++i)
{
cin >> n;
cout << setiosflags(ios::fixed);
cout.precision(2);
cout << SUM(n) << endl;
}
}
return 0;
#include <iomanip>
using namespace std;
double SUM(int x)
{
if(x == 1) return 1;
else
{
int j, a = 1;
double sum = 0.0;
for(j = 0; j < x; ++j)
{
sum = sum + a*(1.0/(j+1));
a *= -1;
}
return sum;
}
}
int main()
{
int m, n;
int i, x;
while(cin >> m)
{
for(i = 0; i < m; ++i)
{
cin >> n;
cout << setiosflags(ios::fixed);
cout.precision(2);
cout << SUM(n) << endl;
}
}
return 0;
}
这道题最关键的是注意数据要用.0模式!不然不会得到正确结果。