Python写数据结构:栈(顺序存储结构)

#!/usr/bin/python3.5
#_*_coding:utf-8_*_

class Stack():
def __init__(self,capacity):
self.stack = [None] * capacity
self.capacity = capacity
self.top = -1

def push(self,element):
if self.full():
print('栈满')
return
self.top += 1
self.stack[self.top] = element

def pop(self):
if self.empty():
print('栈是空的')
return
element = self.stack[self.top]
self.stack[self.top] = None
self.top -= 1
return element

def empty(self):
return self.top == -1

def full(self):
return self.top == self.capacity - 1

def length(self):
return self.top + 1

def getTop(self):
if self.top == -1:
print('栈是空的')
return
return self.stack[self.top]

def clear(self):
while self.top != -1:
self.stack[self.top] = None
self.top -= 1
if __name__ == '__main__':
stack = Stack(10)