How can I implement a stack in C++11?

How can I implement a stack in C++11?

You can implement a stack in C++11 using the Standard Template Library (STL) or by creating your own class. Would you like to see both methods?

Yes, please show me the STL method first.

Sure! You can use the std::stack class from the STL. Here's a simple example:

#include <iostream>
#include <stack>

int main() {
    std::stack<int> myStack;
    myStack.push(1);
    myStack.push(2);
    myStack.push(3);

    while (!myStack.empty()) {
        std::cout << myStack.top() << std::endl;
        myStack.pop();
    }
    return 0;
}

This code pushes three integers onto the stack and then pops them off, printing each one.

Great! Now can you show me how to implement a stack from scratch?

Absolutely! Here's a simple implementation of a stack using a linked list:

#include <iostream>

class Node {
public:
    int data;
    Node* next;
    Node(int val) : data(val), next(nullptr) {}
};

class Stack {
private:
    Node* top;
public:
    Stack() : top(nullptr) {}
    ~Stack() { while (top) pop(); }

    void push(int val) {
        Node* newNode = new Node(val);
        newNode->next = top;
        top = newNode;
    }

    void pop() {
        if (top) {
            Node* temp = top;
            top = top->next;
            delete temp;
        }
    }

    int peek() {
        return top ? top->data : -1; // Return -1 if stack is empty
    }

    bool isEmpty() {
        return top == nullptr;
    }
};

int main() {
    Stack myStack;
    myStack.push(10);
    myStack.push(20);
    std::cout << myStack.peek() << std::endl; // Outputs 20
    myStack.pop();
    std::cout << myStack.peek() << std::endl; // Outputs 10
    return 0;
}

This code defines a Stack class with basic operations.