Lista Circolare

template <class H> class CircularList{
    Nodo<H> *head, *current;
    int n;

    Nodo<H>* _search(H x){
        Nodo<H>* tmp = head->getNext();
        while(tmp != head && *tmp->getKey() != x)
            tmp = tmp->getNext();
        return tmp;
    }

public:
    CircularList(){
        head = new Nodo<H>();
        head->setNext(head);
        head->setPrev(head);
        n = 0;
    }

    void insert(H x){
        Nodo<H>* nd = new Nodo<H>(new H(x));
        if(isEmpty()){
            nd->setNext(head);
            nd->setPrev(head);
            head->setNext(nd);
            head->setPrev(nd);
        }else{
            nd->setNext(head->getNext());
            nd->setPrev(head);
            head->getNext()->setPrev(nd);
            head->setNext(nd);
        }
        n++;
    }

    void del(H x){
        Nodo<H>* tmp = _search(x);
        if(tmp != head){
            tmp->getNext()->setPrev(tmp->getPrev());
            tmp->getPrev()->setNext(tmp->getNext());
            delete tmp;
            n--;
        }
    }

    H* begin(){
        current = head;
        if(head->getNext()) return next();
        return NULL;
    }

    H* next(){
        if(current->getNext() == head) return NULL;
        current = current->getNext();
        return current->getKey();
    }

    int isEmpty(){ return n == 0; }
    int getSize(){ return n; }
};