递归计算n!

package constxiong.interview;/** * 递归计算n的阶乘 * @author ConstXiong */public class TestRecursionNFactorial {public static void main(String[] args) {System.out.println(recursionN(5));}/** * 递归计算n的阶乘 * @param n * @return */private static int recursionN(int n) {if (n <1) {throw new IllegalArgumentException("参数必须大于0");} else if (n == 1) {return 1;} else {return n * recursionN(n - 1);}}}