u Calculate e

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 39381    Accepted Submission(s): 17893

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.

#include<iostream>
#include<iomanip>
using namespace std;

int main()
{
cout<<"n "<<"e"<<endl;
cout<<"- -----------"<<endl;
double e[10]={0};
e[0]=1;
cout<<0<<" "<<fixed<<setprecision(0)<<e[0]<<endl;
for(int i=1;i<10;i++)
{
double temp=1.0*i;
for(int j=i-1;j>0;j--)
{
temp*=j;
}
e[i]=e[i-1]+1/temp;
if(i==1)
{
cout<<i<<" "<<fixed<<setprecision(0)<<e[i]<<endl;
}
else if(i==2)
{
cout<<i<<" "<<fixed<<setprecision(1)<<e[i]<<endl;
}
else
{
cout<<i<<" "<<fixed<<setprecision(9)<<e[i]<<endl;
}
}
return 0;
}

u Calculate e

原文：http://www.cnblogs.com/honeybusybee/p/5221957.html