> >e的有效位(包括整数的2)一共有10位,就得setprecision(10);呵呵~~
#include<iostream>
using namespace std;
void main(){
	cout<<"n e\n"
	    <<"- -----------\n"
        <<"0 1\n"
        <<"1 2\n"
        <<"2 2.5\n"
        <<"3 2.666666667\n"
        <<"4 2.708333333\n"
		<<"5 2.716666666\n"
		<<"6 2.718055555\n"
		<<"7 2.718253968\n"
		<<"8 2.718278770\n"
		<<"9 2.718281526"<<endl;
}