详解python数据结构之栈stack

class Stack():
    def __init__ (self,size):
        self.size = size #栈空间大小
        self.top = -1 #栈中进入一个数据 top 加 1
        self.stack = [] 

    def display_stack(self):#栈stack的打印
        print(self.stack)

if __name__ == "__main__":
    stack = Stack(5) #设定栈空间
    stack.display_stack() #打印栈数据

class Stack():
    def __init__ (self,size):
        self.size = size
        self.top = -1
        self.stack = [] #进栈数据列表
    def display_stack(self):
        print(self.stack)
        
    def push_stack(self,data):
        if len(self.stack ) >= self.size: #当数据数量大于设置的空间，则栈溢出
            print("stack over flow!")
            return
        self.stack.append(data) #没有栈溢出就将数据追加到列表中
        self.top += 1 #栈中每增加一个数据就加 1
        
if __name__ == "__main__":
    stack = Stack(5)
    stack.push_stack(0)
    stack.push_stack(1)
    stack.push_stack(2)
    stack.push_stack(3)
    stack.push_stack(4)
    stack.push_stack(5) #stack空间是 5，这里进栈数据时 6 个，即提示栈溢出stack over flow！
    stack.display_stack()

class Stack():
    def __init__ (self,size):
        self.size = size
        self.top = -1
        self.stack = [] #进栈数据列表
    def display_stack(self):
        print(self.stack)   
    def push_stack(self,data):
        if len(self.stack ) >= self.size: 
            print("stack over flow!")
            return
        self.stack.append(data)
        self.top += 1 
	
	def pop_stack(self):
        if self.top <= -1: #当top小于等于初始值 -1 时说明stack数据列表为空
            print("stack is empty!")
            return
        ret = self.stack.pop() #stack数据列表不为空就取出最后进的值，列表数据数量就少一个
        self.top -= 1 
        return ret
        
if __name__ == "__main__":
    stack = Stack(5)
    stack.push_stack(0)
    stack.push_stack(1)
    stack.push_stack(2)
    stack.push_stack(3)
    stack.push_stack(4)
    stack.display_stack()
    #进栈数据有 5 个，出栈函数调用了 6 次，就出现了提示stack is empty!
    ret = stack.pop_stack()
    print(ret)
    stack.display_stack()
    ret = stack.pop_stack()
    print(ret)
    stack.display_stack()
    ret = stack.pop_stack()
    print(ret)
    stack.display_stack()
    ret = stack.pop_stack()
    print(ret)
    stack.display_stack()
    ret = stack.pop_stack()
    print(ret)
    stack.display_stack()
    ret = stack.pop_stack()
    print(ret)
    stack.display_stack()

class Stack():
    def __init__ (self,size):
        self.size = size
        self.top = -1
        self.stack = [] 
    def display_stack(self):
        print(self.stack)   
    def push_stack(self,data):
        if len(self.stack ) >= self.size: 
            print("stack over flow!")
            return
        self.stack.append(data) 
        self.top += 1 

	def peek_stack(self):
        if self.top == -1: #当栈内没有数据时 提示 stack is empty!
            print("stack is empty!")
            return
        peek = self.stack[self.top] #栈不为空时，将栈顶的数据提取出来
        return peek
        
if __name__ == "__main__":
    stack = Stack(5)
    stack.push_stack(0)
    stack.push_stack(1)
    stack.push_stack(2)
    stack.push_stack(3)
    stack.push_stack(4)
    stack.push_stack(5) 
    stack.display_stack()
    peek = stack.peek_stack()
    print(peek)