Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Python Program to Implement a Stack using Linked List
When it is required to implement a stack data structure using a linked list, a method to add (push values) elements to the linked list, and a method to delete (pop values) the elements of the linked list are defined.
Below is a demonstration for the same −
Example
class Node:
def __init__(self, data):
self.data = data
self.next = None
class Stack_structure:
def __init__(self):
self.head = None
def push_val(self, data):
if self.head is None:
self.head = Node(data)
else:
newNode = Node(data)
newNode.next = self.head
self.head = newNode
def pop_val(self):
if self.head is None:
return None
else:
del_Val = self.head.data
self.head = self.head.next
return del_Val
my_instance = Stack_structure()
while True:
print('push <value>')
print('pop')
print('quit')
my_input = input('What action would you like to perform ? ').split()
operation = my_input[0].strip().lower()
if operation == 'push':
my_instance.push_val(int(my_input[1]))
elif operation == 'pop':
del_Val = my_instance.pop_val()
if del_Val is None:
print('The stack is empty.')
else:
print('The deleted value is : ', int(del_Val))
elif operation == 'quit':
breakOutput
push <value> pop quit What action would you like to perform ? push 56 push <value> pop quit What action would you like to perform ? push 78 push <value> pop quit What action would you like to perform ? push 90 push <value> pop quit What action would you like to perform ? pop The deleted value is : 90 push <value> pop quit What action would you like to perform ? quit
Explanation
The ‘Node’ class is created.
Another ‘Stack_structure’ class with required attributes is created.
It has an ‘init’ function that is used to initialize the first element, i.e the ‘head’ to ‘None’.
A method named ‘push_val’ is defined, that helps add a value to the stack.
Another method named ‘pop_val’ is defined, that helps delete a value from the top of the stack, and returns the deleted value.
An instance of the ‘Stack_structure’ is created.
Three options are given, such as ‘push’, ‘pop’, and ‘quit’.
The ‘push’ option adds a specific value to the stack.
The ‘pop’ option deletes the topmost element from the stack.
The ‘quit’ option comes out of the loop.
Based on the input/choice by user, the respective operations are performed.
This output is displayed on the console.
4K+ Views
