计算阶乘 n! = 1 * 2 * 3 * ... * n

# -*- conding:utf-8 -*-
def jieChen(n):
    if n ==1:
        return 1
    else:
        return n * jieChen(n-1)
def main():
    n = int(input("请输入一个正整数： "))
    x = jieChen(n)
    print("%d 的阶乘为：%d" %(n,x))
main()