Lecture 150:-Stack Class - 2 

Certainly, let's continue building on the stack class. In this version, we'll implement a stack using a linked list, which allows for dynamic resizing without a fixed maximum size.

Here's an implementation of a stack class using a linked list:

cppCopy code

#include <iostream> class Node { public: int data; Node* next; Node(int value) : data(value), next(nullptr) {} }; class Stack { private: Node* top; // Pointer to the top of the stack public: Stack() : top(nullptr) {} bool isEmpty() { return top == nullptr; } void push(int value) { Node* newNode = new Node(value); newNode->next = top; top = newNode; } int pop() { if (isEmpty()) { std::cout << "Stack is empty." << std::endl; return -1; // Return a special value to indicate underflow } Node* temp = top; int poppedValue = temp->data; top = top->next; delete temp; return poppedValue; } int peek() { if (isEmpty()) { std::cout << "Stack is empty." << std::endl; return -1; // Return a special value to indicate underflow } return top->data; } ~Stack() { while (!isEmpty()) { pop(); } } }; int main() { Stack stack; stack.push(10); stack.push(20); stack.push(30); std::cout << "Top element: " << stack.peek() << std::endl; std::cout << "Popping elements: "; while (!stack.isEmpty()) { std::cout << stack.pop() << " "; } std::cout << std::endl; return 0; }

In this version, the Stack class is implemented using a linked list. The push operation adds a new node to the top of the stack, and the pop operation removes the top node. The peek operation retrieves the value of the top node without removing it. The destructor is implemented to clean up the dynamically allocated memory when the stack object is destroyed.

This linked-list-based implementation of a stack allows for dynamic resizing and is more memory-efficient compared to a fixed-size array-based implementation.