poj 1517 u Calculate e

u Calculate e

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 19465		Accepted: 11362		Special Judge

Description

A simple mathematical formula for e is 
e=Σ_0<=i<=n1/i!
where n is allowed to go to infinity. This can actually yield very accurate approximations of e using relatively small values of n.

Input

No input

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 Input

no input

Sample Output

n e
- -----------
0 1
1 2
2 2.5
3 2.666666667
4 2.708333333
...

#include<stdio.h>
#include<string.h>
#include<cstdio>
#include<string>
#include<math.h>
#include<algorithm>
#define LL long long
#define PI atan(1.0)*4
#define DD double
#define MAX 2002000
#define mod 100
#define dian 1.000000011
#define INF 0x3f3f3f
using namespace std;
int main()
{
    LL n,m,j,i,t,k;
    printf("n e\n");
	printf("- -----------\n");
	DD sum=0;
	printf("0 1\n");
	for(i=1;i<=9;i++)
	{
		printf("%d ",i);
		DD ans=1;
		for(j=1;j<=i;j++)
			ans*=j;
		sum+=1/ans;
		printf("%.10g\n",sum+1);
	}
	return 0;
}