u Calculate e hdu 1012

u Calculate e

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 24888    Accepted Submission(s): 11072

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
  

 

Source

Greater New York 2000

 

Recommend

JGShining

 

 

很水的题目，分类就好了

 

 

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int main()
{
    int i,j,s,n;
    int num=0;
    double e;
    int a[10]={1,1,2,6,24,120,720,5040,40320,362880};
    printf("n e\n");
    printf("- -----------\n");
    while(num<=9)
    {
        printf("%d ",num);
        e=0;
        for(i=0;i<=num;i++)
        {
            e=e+1/(a[i]*1.0);
        }
        if(num==0)
        printf("1\n");
        else
        if(num==1)
        printf("2\n");
        else
        if(num==2)
        printf("2.5\n");
        else
        if(num>2)
        printf("%.9lf\n",e);
        num++;
    }
  return 0;
}