#include <iostream>

using namespace std;

class Element
{
	private:
		int v;
		Element* next;

	public:
        Element()
        {
            v = 0;
            next = nullptr;
        }
        Element(int x, Element* next)
        {
            v = x;
            this->next = next;
        }
        int getValue()
        {
            return v;
        }
        void setValue(int v)
        {
            this->v = v;
            this->v = v;
        }
        Element* getNext()
        {
            return next;
        }
        void setNext(Element* p)
        {
            next = p;
        }
};

class LinkedList
{
    private:
        Element* head;                    
        Element* tail;                   
        int size;

    public:
        LinkedList()
        {
            head = nullptr;
            tail = nullptr;
            size = 0;
        }
        bool empty()
        {
            if (size == 0)
                return true;
            else
                return false;
        }
        int getSize()
        {
            return size;
        }
        Element* getFirst()
        {
            return head;
        }
        Element* getLast()
        {
            return tail;
        }
        Element* getNext(Element* p)
        {
            return p->getNext();
        }
        Element* getPrev(Element* p)
        {
            Element* tmp = head;

            do
            {
                if (tmp->getNext() == p)
                    return tmp;
                else
                    tmp = tmp->getNext();
            } while (tmp->getNext() != p);

            return nullptr;
        }
        int retrive(Element* p)
        {
            return p->getValue();
        }
        Element* locate(int x)
        {
            Element* tmp = head;

            for(int i = 0; i < size; i++)
            {
                tmp = tmp->getNext();
                if (tmp->getValue() == x)
                    return tmp;
            }

            return nullptr;
        }
        void append(int x)
        {
            if (empty())
            {
                head = new Element(x, nullptr);
                tail = head;
            }
            else
            {
                tail->setNext(new Element(x, nullptr));
                tail = tail->getNext();
            }

            size++;
        }
        void insert(Element* p, int x)
        {
            p->setValue(x);
        }
        void del(Element* p)
        {
            if (p == head)
            {
                head = head->getNext();
                delete p;
                if (head == nullptr)
                    tail = nullptr;
            }
            else
            {
                Element* tmp = getPrev(p);
                tmp->setNext(getNext(p));
                delete p;
                if (getNext(tmp) == nullptr)
                    tail = tmp;
            }

            size--;
        }
        void clear()
        {
            Element* tmp;

            while (head != nullptr)
            {   
                tmp = getNext(head);
                delete head;
                head = tmp;
            }  
        }
        friend ostream& operator<<(ostream& out, LinkedList* l)
        {
            Element* tmp = l->head;

            for (int i = 0; i < l->getSize(); i++)
            {
                out << tmp->getValue() << " | ";
                tmp = tmp->getNext();
            }

            return out;
        }
        void insert(int p, int x)
        {
            Element* tmp = head;

            for (int i = 0; i < p; i++)
            {
                tmp = tmp->getNext();
            }

            Element* tmp2 = tmp;
            
            for (int i = p; i < size; i++)
            {
                tmp->setValue(x);
                tmp->setNext(tmp2);
                tmp = tmp2;
                tmp2 = tmp2->getNext();
            }

            size++;

            tail = tmp2;
        }
        void del(int p)
        {
            Element* tmp = head;

            for (int i = 0; i < p; i++)
            {
                tmp = tmp->getNext();
            }

            del(tmp);
        }
        ~LinkedList();
};


int main()
{
    //Zadanie 5.1 - test
    cout << endl << "Zadanie 5.1 - test" << endl;

    LinkedList* a = new LinkedList();

    cout << endl << "empty(): 1 - " << a->empty();
    cout << endl << "getSize():  0 - " << a->getSize();
    cout << endl << "append(4): 4 | - "; a->append(4); cout << " " << a;
    cout << endl << "append(6): 4 | 6 | - "; a->append(6); cout << " " << a;
    //cout << endl << ": -" << ;
    cout << endl << "retrive(getPrev(tail)): 4 - " << a->retrive(a->getPrev(a->getLast()));
    cout << endl << "locate(6): adress - " << a->locate(6);
    cout << endl << "locate(7): nullptr - " << a->locate(7);


	return 0;
}