阶乘公式求值

解题思路:

注意事项:

参考代码:

import java.util.Scanner;

public class Main {

    // 计算阶乘

    public static double fact(int x){

        if(x==0){

            return 1.0;

        }else{

            return x*fact(x-1);

        }

    }

    public static void main(String [] args){

        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();

        double sum = 0.0;

        for(int i=1; i<=n; i++){

            double he = 1 / fact(i); // 计算每一项的倒数

            sum += he; // 累加每一项的和

        }

        System.out.printf("sum=%.5f", sum);

    }

}