#! /usr/bin/env python
#coding=utf-8
#Python实现基本数据结构---栈操作
class Stack(object):
  def __init__(self,size):
    self.size = size
    self.stack = []
    self.top = 0#初始化，top=0时则为空栈
  def push(self,x):
    if self.stackFull():#进栈之前检查栈是否已满
      raise Exception("overflow !")
    else:
      self.stack.append(x)
      self.top=self.top+1#push进去的第一个元素下标为1
  def pop(self):
    if self.stackEmpty():
      raise Exception("underflow !")
    else:
      self.top=self.top-1
      return self.stack.pop()#利用Python内建函数pop()实现弹出
  def stackEmpty(self):
    if self.top == 0:#判断栈空
      return True
    else:
      return False
  def stackFull(self):
    if self.top == self.size:#判断栈满！！！
      return True
    else:
      return False
if __name__ == '__main__':
  print "编程素材网测试结果："
  s=Stack(10)
  for i in range(3):
    s.push(i)
  print s.stack
  print s.pop()
  print s.stack
  print s.pop()
  print s.pop()
  print s.stack
  print s.stackEmpty()
  print s.stackFull()
  for i in range(10):
    s.push(i)
  print s.stackFull()