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;

}