用python实现栈
闲话不说，上代码#! /usr/bin/python
class PopOnEmptyStackError(Exception):
'''A user-defined exception class.'''
def __init__(self):
Exception.__init__(self)
class Stack:
def __init__(self):
self.data = []
def empty(self):
if (len(self.data)==0):
return True
else:
return False
def push(self,item):
self.data.append(item)
def pop(self):
try:
if (len(self.data)==0):
raise PopOnEmptyStackError
else:
self.data.pop()
except PopOnEmptyStackError:
print "you can not pop an empty stack!\n"
def show(self):
for i in range(0,len(self.data)):
print (self.data)
# 以下是简单测试
st = Stack()
#st.push(1)
#st.push(2)
st.pop()
st.show()
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