python-实现顺序栈

 7 class sqstack(object):
  8     def __init__(self,maxsize):
  9         self.maxsize = maxsize
 10         self.stackElem = []
 11         self.top = 0
 12
 13     def clear(self):
 14         self.top = 0
 15     def isEmpty(self):
 16         return self.top == 0
 17     def length(self):
 18         return self.top
 19     def gettop(self):
 20         if not self.isEmpty():
 21             return self.stackElem[self.top - 1]
 22         else:
 23             return None
 24     def push(self,item):
 25         if self.top ==  self.maxsize:
 26             raise Exception("栈已满")
 27         else:
 28             self.stackElem.append(item)
 29             self.top += 1
 30     def pop(self):
 31         if self.isEmpty():
 32             return None
 33         else:
 34             self.top -= 1
 35             values =  self.stackElem[self.top]
 36             del self.stackElem[self.top]
 37             return values
 38     def display(self):
 39         for i in self.stackElem:
40             print(i,end = " ")
 41         print()
 42
 43 if __name__ == "__main__":
 44     sqstack1 = sqstack(5)
 45     sqstack1.push(1)
 46     sqstack1.push(2)
 47     sqstack1.push(3)
 48     sqstack1.push(4)
 49     sqstack1.push(5)
 50     print(sqstack1.gettop())
 51     sqstack1.display()
 52     print(sqstack1.length())
 53     print(sqstack1.pop())
 54     sqstack1.display()

运行结果：

5
1 2 3 4 5
5
5
1 2 3