class Stack(object):

"""

stack by python

filo先入后出

默认容量为4

"""

def __init__(self, capacity=4):

self.clear()

self.capacity = capacity

# 计数

def count(self):

return self.height

# 判满

def full(self):

if self.height == self.capacity:

return True

return False

# 判空

def empty(self):

if self.height == 0:

return True

return False

# 清空栈

def clear(self):

self.top = 0

self.height = 0

self.__stack = []

# 插入栈 -filo

def push(self, value):

if self.full():

return False

self.__stack.append(value)

self.height += 1

self.top += 1

# 出栈 -filo

def pop(self):

if self.empty():

return False

value = self.__stack.pop()

self.height -= 1

self.top -= 1

return value

# 实现迭代

def __iter__(self):

self.index = -1

return self

def __next__(self):

self.index += 1

if self.index == self.height:

raise StopIteration

return self.__stack[self.index]