hdoj1012--u Calculate e

Problem Description

A simple mathematical formula for e is



where n is allowed to go to infinity. This can actually yield very accurate approximations of e using relatively small values of n.

 

Output

Output the approximations of e generated by the above formula for the values of n from 0 to 9. The beginning of your output should appear similar to that shown below.

Sample Output

n e

- -----------

0 1

1 2

2 2.5

3 2.666666667

4 2.708333333

#include<iostream>
#include <iomanip>

using namespace std;

int main()
{
    int i,n;
    double s,t;
    cout<<"n e"<<endl;
    cout<<"- -----------"<<endl;
    cout<<"0 1"<<endl;
    cout<<"1 2"<<endl;
    cout<<"2 2.5"<<endl;
    s=2.5;
    n=2;
    for(i=3; i<=9; i++)
    {
        n=i*n;
        s+=1.0/n;
        cout<<i<<" "<<fixed<<setprecision(9)<<s<<endl;
    }
    return 0;
}