Python 实现一个栈

# -*- coding=utf-8 -*-
# 堆栈的top可以预先指定，实时变更，也可以只求stack长度，实时汇报

class Stack(object):
    def __init__(self, size):
        self.stack = []
        self.size = size
        # self.top = len(self.stack)

    @property
    def top(self):
        return len(self.stack)

    def isfull(self):
        return self.top == self.size

    def isempty(self):
        return self.top == 0

    def push(self, new_value):
        if not self.isfull():
            self.stack.append(new_value)
            # self.top += 1
        else:
            raise Exception('stack is full')

    def pop(self):
        if not self.isempty():
            self.stack.pop()
            # self.top -= 1
        else:
            raise Exception('stack is empty')

    def show(self):
        print self.stack


s = Stack(10)
print s.top
for i in range(10):
    s.push(i)

print s.stack
print s.top
# for i in range(11):
#     s.pop()