#ifndef LISTADT_H
#define LISTADT_H

#include <iostream>

using namespace std;

//typedef int ItemType;
template <class ItemType>
class NodeType
{
public:
	ItemType info;
	NodeType<ItemType> * nextPtr;
};

template <class ItemType>
class List
{
public:
	List();
	void makeEmpty();
	bool isEmpty();
	void goToStart();
	void goToNext();
	bool isAtEnd();
	ItemType CurrentItem();
	void insert(ItemType);
	void deleteCurrentItem();
	int currentPosition();
private:
	NodeType<ItemType> * head;
	NodeType<ItemType> * current;
	NodeType<ItemType> * previous;
	int position;
};


template <class ItemType>
List<ItemType>::List()
{
	head = NULL, current = NULL, previous = NULL;
	position = 1;
}
template <class ItemType>
void List<ItemType>::makeEmpty()
{
	if (!isEmpty())
	{
		goToStart();
		while (!isAtEnd())
		{
			goToNext();
			delete previous;
			previous = current;
		}
		head = NULL;
		current = NULL;
		previous = NULL;
		position = 1;
	}
}
template <class ItemType>
bool List<ItemType>::isEmpty()
{
	if (head == NULL)
		return true;
	else
		return false;
}
template <class ItemType>
void List<ItemType>::goToStart()
{
	if (position == 1)
		return;
	else
	{
		current = head;
		previous = NULL;
		position = 1;
	}
}
template <class ItemType>
void List<ItemType>::goToNext()
{
	if (!isAtEnd())
	{
		if (current->nextPtr == NULL)
		{
			previous = current;
			current = NULL;
			position += 1;
		}
		else
		{
			previous = current;
			current = current->nextPtr;
			position += 1;
		}
	}
}
template <class ItemType>
bool List<ItemType>::isAtEnd()
{
	if (current == NULL)
		return true;
	else
		return false;
}
template <class ItemType>
ItemType List<ItemType>::CurrentItem()
{
	if (!isAtEnd())
		return current->info;
}
template <class ItemType>
void List<ItemType>::insert(ItemType num)
{
	NodeType<ItemType> * temp;
	temp = new NodeType<ItemType>;
	temp->info = num;

	if (head == NULL)
	{
		temp->nextPtr = NULL;
		head = temp;
		current = head;
	}
	else if (position == 1)
	{
		head = temp;
		head->nextPtr = current;
		current = head;
	}
	else if (!isAtEnd() && current->nextPtr == NULL)
	{
		temp->nextPtr = current;
		current = temp;
		if (previous != NULL)
		{
			previous->nextPtr = current;
		}
	}
	else
	{
		previous->nextPtr = temp;
		temp->nextPtr = current;
		current = temp;
	}
}
template <class ItemType>
void List<ItemType>::deleteCurrentItem()
{
	if (head == NULL)
	{
		cout << "List is empty." << endl;
	}
	else
	{
		if (current == head)
		{
			head = head->nextPtr;
			current->nextPtr = 0;
			delete current;
			current = head;
		}
		else if (isAtEnd())
		{
			cout << "End of list cannot delete. Move the the start of list." << endl;
		}
		else if (current->nextPtr == NULL)
		{
			delete current;
			current = 0;
			previous->nextPtr = NULL;
			current = previous->nextPtr;
		}
		else
		{
			previous->nextPtr = current->nextPtr;
			current->nextPtr = 0;
			delete current;
			current = previous->nextPtr;
		}
	}
}
template <class ItemType>
int List<ItemType>::currentPosition()
{
	return position;
}

#endif