#!/usr/bin/env python

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

class Stack(object):

"""docstring for Stack"""

def __init__(self, cap):

super(Stack, self).__init__()

self.__cap = cap # 栈大小

self.__length = 0 # 栈长度

if self.__cap < 0:

raise ValueError("length of Stack can not be negtive")

self.__values = [0 for x in xrange(0, self.__cap)]

def empty(self):

return self.__length is 0

def push(self, x):

if self.__length >= self.__cap:

raise IndexError("stack is full, can not push any object")

self.__values[self.__length] = x

self.__length += 1

def pop(self):

if self.__length <= 0:

return None

self.__length -= 1

return self.__values[self.__length]

def __str__(self):

return "".join(["Stack, Value: ", str(self.__values), " cap: ", str(self.__cap),

" length:", str(self.__length)])

def main():

stack = Stack(5)

for x in xrange(0, 5):

stack.push(x)

print "full stack"

print stack

print "pop everything"

for x in xrange(0, 7):

print stack.pop()

print "index of bound error"

for x in xrange(0, 7):

stack.push(x)

if __name__ == '__main__':

main()