doubleLinkedList.cpp

#include <iostream>

using namespace std;

template <typename N> class Node{
    private:
        N key;
        Node<N> *next, *prev;

    public:
        Node(N key){
            this->key = key;
            next = prev = NULL;
        }
        int getKey() { return key; }
        Node<N>* getNext() { return next; }
        void setNext(Node<N>* next) { this->next = next; }
        Node<N>* getPrev() { return prev; }
        void setPrev(Node<N>* prev) { this->prev = prev; }
};

template <typename L> class List{
    private:
        Node<L>* head, *tail;
        int size;

        Node<L>* _search(L x){
            Node<L>* temp = head;

            while(temp!=NULL)
            {
                if(temp->getKey() == x)
                    return temp;
                temp = temp->getNext();
            }
            return NULL;
        }
    public:
        List(){
            head = tail = NULL;
            size = 0;
        }

        int isEmpty() {
            if(!head)
                return 1;
            return 0;
        }

        int getSize() { return size; }

        int search(L x){
            if(_search(x))
                return 1;
            return 0;
        }

        List<L>* insertInHead(L x){
            Node<L>* temp = new Node<L>(x);
            size++;
            if(!head){
                head = tail = temp;
                return this;
            }
            temp->setNext(head);
            head->setPrev(temp);
            head = temp;
            return this;
        }

        List<L>* insertInTail(L x){
            if(!head){
                return insertInHead(x);
            }
            Node<L>* temp = new Node<L>(x);
            size++;
            tail->setNext(temp);
            temp->setPrev(tail);
            tail = temp;
            return this;
        }

        void del(L x){
            if(!search(x)){
                cout << "Elemento Inesistente" << endl;
                return;
            }
            size--;
            Node<L>* temp = _search(x);
            if(temp == head){
                head = temp->getNext();
                delete(temp);
                return;
            }
            Node<L>* previous = temp->getPrev();
            previous->setNext(temp->getNext());
            Node<L>* temp2 = temp->getNext();
            if(temp2)
                temp2->setPrev(previous);
            delete(temp);
        }

        void print(){
            if(isEmpty()){
                cout << "La Lista è vuota!" << endl;
                return;
            }
            Node<L>* temp = head;
            while(temp){
                cout << temp->getKey() << " ";
                temp = temp->getNext();
            }
            cout << endl;
        }

};

int main(){
    List<int>* T = new List<int>();
    T->insertInHead(5)->insertInTail(567)->insertInHead(6)->insertInTail(8)->insertInHead(45);
    T->print();
    T->del(6);
    T->print();
    T->del(8);
    T->print();
    T->del(5);
    T->print();
    T->del(567);
    T->print();
    T->del(45);
    T->print();

    return 0;
}