题目：利用递归方法求5!。

程序分析：递归公式：fn=fn_1*4!

程序设计：

import java.util.Scanner;public class Ex22 {public static void main(String[] args) { Scanner s = new Scanner(System.in); int n = s.nextInt(); Ex22 tfr = new Ex22(); System.out.println(tfr.recursion(n)); } public long recursion(int n) { long value = 0 ; if(n ==1 || n == 0) { value = 1; } else if(n > 1) { value = n * recursion(n-1); } return value;} }

方法二利用递归方法求5!。

public class lianxi22 {public static void main(String[] args) { int n = 5; rec fr = new rec(); System.out.println(n+"! = "+fr.rec(n));}}class rec{public long rec(int n) { long value = 0 ; if(n ==1 ) { value = 1; } else { value = n * rec(n-1); } return value;}}