# !/usr/bin/env python

# -*- coding: utf-8 -*-

__author__ = 'MrHero'

class Node(object):

# 节点

def __init__(self, data=None):

self.data = data

self.next = None

class LKStack(object):

def __init__(self):

self.top = Node(None)

self.count = 0

def get_length(self):

return self.count

def get_top(self):

# 返回栈顶元素

return self.top.data

def is_empty(self):

return self.count == 0

def push(self, elem):

# 进栈

tmp = Node(elem)

if self.is_empty():

self.top = tmp

else:

tmp.next = self.top

self.top = tmp

self.count += 1

def pop(self):

# 出栈

if self.is_empty():

raise IndexError("Stack is empty!")

else:

self.count -= 1

elem = self.top.data

self.top = self.top.next

return elem

def show_stack(self):

# 从栈顶开始显示各节点值

if self.is_empty():

raise IndexError("Stack is empty!")

else:

j = self.count

tmp = self.top

while j > 0 and tmp:

print tmp.data

tmp = tmp.next

j -= 1

if __name__ == '__main__':

lks = LKStack()

for i in range(1, 5):

lks.push(i)

lks.show_stack()

lks.pop()

lks.show_stack()