Python program to demonstrate all stack operations using a doubly linked list

Write a python program to demonstrate all stack operations using a doubly linked list  :


Answer:

class Node:
 
    def __init__(self, data):
        self.data = data # Assign data
        self.next = None # Initialize next as null
        self.prev = None # Initialize prev as null       
         

class Stack:
    # Function to initialize head 
    def __init__(self):
        self.head = None

    def push(self, data):
 
        if self.head is None:
            self.head = Node(data)
        else:
            new_node = Node(data)
            self.head.prev = new_node
            new_node.next = self.head
            new_node.prev = None
            self.head = new_node
             

    def pop(self):
 
        if self.head is None:
            return None
        else:
            temp = self.head.data
            self.head = self.head.next
            self.head.prev = None
            return temp
 
 

    def top(self):
 
        return self.head.data
 
 

    def size(self):
 
        temp = self.head
        count = 0
        while temp is not None:
            count = count + 1
            temp = temp.next
        return count
           
    def isEmpty(self):
 
        if self.head is None:
           return True
        else:
           return False
             

    def printstack(self):
         
        print("stack elements are:")
        temp = self.head
        while temp is not None:
            print(temp.data, end ="->")
            temp = temp.next         
         
 
       
if __name__=='__main__': 
 

  stack = Stack()
 
  print("Stack operations using Doubly LinkedList")
  stack.push(4)
 

  stack.push(5)
 

  stack.push(6)
 

  stack.push(7)
 
  stack.printstack()
 

  print("\nTop element is ", stack.top())
 

  print("Size of the stack is ", stack.size())
 

  stack.pop()
 

  stack.pop()
   


  stack.printstack()
   

  print("\nstack is empty:", stack.isEmpty())




Output:
Stack operations using Doubly LinkedList
stack elements are:
7->6->5->4->
Top element is  7
Size of the stack is  4
stack elements are:
5->4->
stack is empty: False