java输入n（n<13),计算1！+2！+3！+……+n！

下面是Java代码实现输入n（n<13),计算1！+2！+3！+……+n！的值：

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        System.out.println("输入n,打印1!+2!+3!+...+n!的值");
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        while (n < 1 || n > 12) {//保证输入的数字大于0且小于13
            System.out.println("请输入大于0且小于13的数字:");
            n = in.nextInt();
        }
        int sum = 0;
        for (int i = 1; i <= n; ++i)
            sum += recursion(i);
        System.out.println(sum);
    }

    //递归函数,求n!
    public static int recursion(int n) {
        if (n == 1)
            return 1;
        else
            return n * recursion(n - 1);
    }
}