阶乘2种方法

                                                      **阶乘**

'''
1*1
1*2
1*2*3*4
1*2*3*4*5
1*2*3*4*5*6
1*2*3*4*5*6*7

sum1(1)*2=sum(2)
sum1(2)*3=sum(3)
sum1(3)*4=sum(4)
sum1(4)*5=sum(5)
sum1(5)*6=sum(6)
sum1(6)*7=sum(7)
'''
def  sum1(n):
    '''
    递归实现阶乘
    :param n: 值
    :return: n!
    '''
    if n==1:
        return 1
    else:
        return n*sum1(n-1)
print(sum1(10))


def func2(num):
    '''
    普通方法实现阶乘
    :param num: 参数
    :return: n!
    '''
    i = 1
    res = 1
    while i<=num:
        res=res*i
        i+=1
    return res
print(func2(1))
print(func2(2))
print(func2(3))
print(func2(4))