标签：os io ios on sp return ip c
#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int main()
{
int i;
cout<<setiosflags(ios::fixed)<<setprecision(20);//控制小数位数
cout<<4*atan(1)<<endl;
return 0;
}
标签：os io ios on sp return ip c
原文地址：http://www.cnblogs.com/bofengyu/p/3909958.html
