《 Skynet 游戏服务器开发实战》

//根据公式计算e
//
//e = sum(i!); i= 0->n;
//
#include <stdio.h>
int Factorial(int n)
{
    if (n <= 1)
    {
        return 1;
    }
    return n*Factorial(n-1);
}

double Calculate_e(int n)
{
    double sum = 0;
    for (int i = 0; i <= n; i++)
    {
        sum += 1/(double)Factorial(i);
    }
    return sum;
}

int main()
{
    printf("n  e\n------------------------\n");
    for (int i = 0; i<10; i++)
    {
        if (i<=1)
        {
            printf("%d  %.0f\n", i, Calculate_e(i));
        }
        else if (i == 2)
        {
            printf("%d  %.1f\n", i, Calculate_e(i));
        }
        else
        {
            printf("%d  %f\n", i, Calculate_e(i));
        }
    }
    return 0;
}