栈

先进后出

pyhton 3.x写不写object都可以， class stack(object):
默认写了object，拥有好多操作对象

以前不写object的话，就只有几个默认的操作对象

class Stack():
    def __init__(self,mystack=[]):
        self._stack = mystack
    def push(self,data):
        self._stack.append(data)
    def pop(self):
        self._stack.pop()
    def is_empty(self):
        return len(self._stack) == 0
    def peek(self):
        return self._stack[-1]
    def size(self):
        return len(self._stack)
    def print1(self):
        print(self._stack)
myStack = Stack()
print('原栈：',end='')
myStack.print1()

print('压栈：')
for i in range(5):
    myStack.push(i)
    myStack.print1()
print('出栈:')
for j in range(5):
    myStack.pop()
    myStack.print1()