ZOJ 1113 u Calculate e

u Calculate e

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Time Limit: 2 Seconds      Memory Limit: 65536 KB

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Background

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.

Example

Output

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

题意：按上面公式计算e

思路：题目只要求计算到0～9,而前面几个数字输出后小数跟后面数字不同，所以先输出

代码：

#include<stdio.h>


int main()
{
    double arr[10]={1};
    int i=1,j=3;
    while(i<10)
    {
        arr[i]=i*arr[i-1];
        i++;
    }
    printf("n e\n");
    printf("- -----------\n");
    printf("0 1\n1 2\n2 2.5\n");
    double sum=2.5;
    while(j<10)
    {
        sum+=1.0/arr[j];
        printf("%d %.9lf\n",j,sum);
        j++;
    }
    return 0;
}