reverse.cpp

#include <iostream>

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

class LinkedList {
public:
    Node* head;

    LinkedList() : head(nullptr) {}

    void append(int val) {
        Node* newNode = new Node(val);
        if (!head) {
            head = newNode;
            return;
        }
        Node* temp = head;
        while (temp->next) {
            temp = temp->next;
        }
        temp->next = newNode;
    }

    void reverse() {
        Node* prev = nullptr;
        Node* current = head;
        Node* next = nullptr;

        while (current) {
            next = current->next; // Store next node
            current->next = prev; // Reverse the link
            prev = current;       // Move prev forward
            current = next;       // Move current forward
        }
        head = prev; // Update head to new first element
    }

    void print() {
        Node* temp = head;
        while (temp) {
            std::cout << temp->data << " ";
            temp = temp->next;
        }
        std::cout << std::endl;
    }
};

int main() {
    LinkedList list;
    list.append(1);
    list.append(2);
    list.append(3);
    list.append(4);

    std::cout << "Original List: ";
    list.print();

    list.reverse();

    std::cout << "Reversed List: ";
    list.print();

    return 0;
}