利用递归和循环求阶乘

求一个数的阶乘

//求一个数的阶乘
public class Test_2 {

    public static int f1(int n) { // 递归
        if (n == 1 || n == 0)
            return 1;
        else
            return n * f1(n - 1);
    }

    public static void f2(int a) { // 循环
        long sum = 1;
        for (int i = 1; i <= a; i++) {

            sum *= i;

        }
        System.out.println(sum);
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        System.out.println(f1(a));
        f2(a);
    }
}