Doubly_LinkedList.h

#ifndef DOUBLY_LINKEDLIST_H
#define DOUBLY_LINKEDLIST_H

#include <iostream>
#include <cassert>
#include <vector>
#include <algorithm>

#define edl '\n'

template <class T>
struct D_Node
{
    T data{};
    D_Node<T> *next{};
    D_Node<T> *prev{};
    D_Node(T data) : data(data) {}
    void set(D_Node<T> *next, D_Node<T> *prev)
    {
        this->next = next;
        this->prev = prev;
    }
    // ~D_Node() { std::cout << "Destroy value: " << data << " at address " << this << edl; }
};

template <class type>
class Doubly_LinkedList
{
    D_Node<type> *head{};
    D_Node<type> *tail{};
    int length{};

    void delete_node(D_Node<type> *node);
    void link(D_Node<type> *first, D_Node<type> *second);
    void add_node_between_node_and_next(D_Node<type> *node_before, type val);
    D_Node<type> *delete_and_link(D_Node<type> *cur);
    void delete_and_link_v2(D_Node<type> *cur);

public:
    Doubly_LinkedList();
    ~Doubly_LinkedList();
    Doubly_LinkedList(const Doubly_LinkedList &) = delete;
    Doubly_LinkedList &operator=(const Doubly_LinkedList &another) = delete;
    // Returns the length (number of nodes) of the doubly linked list.
    const int get_length();
    // Returns the value at the given index.
    const type get_value(int idx);
    // Inserts a new node with the given value at the end of the doubly linked list.
    void insert_end(type val);
    // Inserts a new node with the given value at the beginning of the doubly linked list.
    void insert_front(type val);
    // Inserts a new node with the given value into the list while maintaining sorted order.
    void insert_sorted(type val);
    // Prints the values of all nodes in the doubly linked list
    void print();
    // Prints the values of nodes in reverse order
    void print_reversed();
    // Removes and returns the value of the node at the front of the doubly linked list.
    type pop_front();
    // Removes and returns the value of the node at the end of the doubly linked list.
    type pop_back();
    // Deletes the first occurrence of the node containing the specified value from the doubly linked list.
    void delete_node_with_key(type val);
    // Deletes all nodes with a specific value from the doubly linked list.
    void delete_all_nodes_with_key(type val);
    // Deletes nodes at even positions (0-based index) from the doubly linked list.
    void delete_even_positions();
    // Deletes nodes at odd positions (0-based index) from the doubly linked list.
    void delete_odd_positions();
    // Checks if the doubly linked list is a palindrome.
    bool is_palindrome();
    // Returns the middle value of the doubly linked list.
    type middle_value_0();
    type middle_value_1();
    // Reverses the order of nodes in the doubly linked list.
    void reverse();
};
#endif