What are some examples of stack implementations in programming?

What are some examples of stack implementations in programming?

Stacks can be implemented using arrays or linked lists. Would you like to see code examples for both?

Yes, please show me the array implementation first.

Here's a simple array-based stack implementation in Python:

class Stack:
    def __init__(self):
        self.stack = []

    def push(self, item):
        self.stack.append(item)

    def pop(self):
        return self.stack.pop() if not self.is_empty() else None

    def is_empty(self):
        return len(self.stack) == 0

    def peek(self):
        return self.stack[-1] if not self.is_empty() else None

Great! Now can you show me the linked list implementation?

Sure! Here's a linked list-based stack implementation in Python:

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

class Stack:
    def __init__(self):
        self.top = None

    def push(self, item):
        new_node = Node(item)
        new_node.next = self.top
        self.top = new_node

    def pop(self):
        if self.is_empty():
            return None
        popped_node = self.top
        self.top = self.top.next
        return popped_node.data

    def is_empty(self):
        return self.top is None

    def peek(self):
        return self.top.data if not self.is_empty() else None