sum=1-1/2!+1/3!-1/4!+…(-1)n-1*1/n用java

以下是Java实现sum=1-1/2!+1/3!-1/4!+…(-1)n-1*1/n的代码：

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double sum = 1, x = -1, f = 1;
        for (int i = 2; i <= n; i++) {
            f *= i;
            sum += x / f;
            x = -x;
        }
        System.out.println("sum=" + sum);
    }
}