Python Program to Implement Stack

«
»

This is a Python program to implement a stack.

Problem Description

The program creates a stack and allows the user to perform push and pop operations on it.

Problem Solution

1. Create a class Stack with instance variable items initialized to an empty list.
2. Define methods push, pop and is_empty inside the class Stack.
3. The method push appends data to items.
4. The method pop pops the first element in items.
5. The method is_empty returns True only if items is empty.
6. Create an instance of Stack and present a menu to the user to perform operations on the stack.

advertisement
Program/Source Code

Here is the source code of a Python program to implement a stack. The program output is shown below.

class Stack:
    def __init__(self):
        self.items = []
 
    def is_empty(self):
        return self.items == []
 
    def push(self, data):
        self.items.append(data)
 
    def pop(self):
        return self.items.pop()
 
 
s = Stack()
while True:
    print('push <value>')
    print('pop')
    print('quit')
    do = input('What would you like to do? ').split()
 
    operation = do[0].strip().lower()
    if operation == 'push':
        s.push(int(do[1]))
    elif operation == 'pop':
        if s.is_empty():
            print('Stack is empty.')
        else:
            print('Popped value: ', s.pop())
    elif operation == 'quit':
        break
Program Explanation

1. An instance of Stack is created.
2. The user is presented with a menu to perform push and pop operations on the stack.
3. The chosen operation is performed by calling the corresponding method of the stack.

Note: Join free Sanfoundry classes at Telegram or Youtube
advertisement
advertisement
Runtime Test Cases
Case 1:
push <value>
pop
quit
What would you like to do? push 3
push <value>
pop
quit
What would you like to do? push 5
push <value>
pop
quit
What would you like to do? pop
Popped value:  5
push <value>
pop
quit
What would you like to do? pop
Popped value:  3
push <value>
pop
quit
What would you like to do? pop
Stack is empty.
push <value>
pop
quit
What would you like to do? quit
 
Case 2:
push <value>
pop
quit
What would you like to do? pop
Stack is empty.
push <value>
pop
quit
What would you like to do? push 1
push <value>
pop
quit
What would you like to do? pop
Popped value:  1
push <value>
pop
quit
What would you like to do? quit

Sanfoundry Global Education & Learning Series – Python Programs.

To practice all Python programs, here is complete set of 150+ Python Problems and Solutions.

advertisement

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & technical discussions at Telegram SanfoundryClasses.