#! /usr/bin/env python
#coding=utf-8
class Queue(object):
  def __init__(self,size):
    self.size=size
    self.head=-1 #初始化队头
    self.tail=-1 #初始化队尾
    self.queue=[]
  def EnQueue(self,x):
    if self.IsFull():#如果试图往满队列插入元素，则发生上溢
      raise Exception("overflow !")
    else:
      self.queue.append(x)
      self.tail += 1 #往队列中加入元素是在尾部进行
  def DeQueue(self):
    if self.IsEmpty():#如果试图从空队列删除元素，则发生下溢
      raise Exception("underflow !")
    else:
      self.head += 1#从队列中删除元素在队头进行，将队头后移
      return self.queue.pop(0)#利用内建函数pop()将队头弹出
  def IsFull(self):#判断队列满
    #return (self.tail+1)%self.size == self.head
    return self.tail-self.head+1==self.size
  def IsEmpty(self):#判断队列空！！！
    return self.head == self.tail
if __name__ == '__main__':
  print "测试结果："
  q=Queue(10)
  for i in range(3):
    q.EnQueue(i)
  print q.queue
  print q.DeQueue()
  print q.queue
  print q.DeQueue()
  print q.IsEmpty()
  print q.DeQueue()
  print q.IsEmpty()
  print q.queue
  for i in range(9):
    q.EnQueue(i)
  print q.queue
  print q.IsFull()