第九周项目二-分数的累加

<img src="http://img.blog.csdn.net/20141025091347572?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvYmFpamllOTg3/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="" />#include<iostream>
using namespace std;
int main()
{
int s=1;
double t,sum=0,i=1;
do
{
t=i/(i+2);
sum=sum+s*t;
s=-s;
i=i+2;
}
while (i<=19);
cout<<sum<<endl;
return 0;
}