hdu_1012_u Calculate e_201310121519

u Calculate e
Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 25494    Accepted Submission(s): 11312

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

#include <stdio.h>

int jc(int n)
{
    int i,sum=1;
    if(n==0)
    return 1;
    if(n>0)
    {
        for(i=1;i<=n;i++)
        sum*=i;
        return sum;
    }
}

int main()
{
    int i,j,e,t,n=9;
    double sum=0;
    printf("n e\n");
    printf("- -----------\n");
    printf("0 1\n");
    printf("1 2\n");
    printf("2 2.5\n");
    for(j=3;j<=n;j++)
    {
        sum=0;
        for(i=0;i<=j;i++)
        {
            t=jc(i);
            sum+=1.0/t;
        }
        printf("%d %.9lf\n",j,sum);
    }
    return 0;
}