Python-函数递归调用

Posted 2021-01-31 bird8868

案例一：汉诺塔

例一：

def move(n, a, buffer, c):
    if n ==1:
        print(‘move‘, a, ‘-->‘, c)
    else:
        move(n-1, a, c, buffer)
        move(1, a, buffer, c)
        move(n-1, buffer, a, c)

move(3, ‘A‘,‘B‘,‘C‘)

例二：

def hanoi(n,x,y,z):
    if n == 1:
        print(x,‘--->‘,z)
    else:
        hanoi(n-1,x,z,y)#将前n-1个盘子移动到y上
        print(x, ‘--->‘, z)#将最底下的盘子移动到z上
        hanoi(n-1,y,x,z)#将y上的n-1个盘子移动到z上
if __name__ == ‘__main__‘:
    num = int(input("请输入汉若塔层数："))
    hanoi(num,‘X‘,‘buffer‘,‘Z‘)

案例二：求阶乘

例一：

def f(n):
    if n == 0:
        sum = 1
    else:
        sum = n * f(n-1)
    return sum
s = int(input(‘输入一个整数：‘))
p = f(s)
print(‘%s!=%s‘ % (s,p))

例二：

def factorial(n):
    res = n
    for i in range(1,n):
        res *= i
    return res
if __name__ == ‘__main__‘:
    num = int(input("请输入一个正整数："))
    result = factorial(num)
    print("%s的阶乘为：%s" % (num,result))

案例三：利用递归将输入的字符串反向输出

def output(str,len):
    if len == 0:
        return
    print(str[len-1])
    output(str,len-1)
s = input("请输入字符串：")
l = len(s)
output(s,l)