#ifndef __LIST_HPP
#define __LIST_HPP

template<class T>
class aList {
	aList& operator=(const aList& l) { return *this; } // don't copy
protected:
	struct aListElement {
		T elem;
		aListElement *prev, *next;
	};
	aListElement *listhead;

	virtual int check(const T e) const { return 1; }
public:
	aList();
	virtual ~aList();

	void append(T e);
	void prepend(T e);
        void insertAt(T e, int pos);
	void clear();
	int empty() const;
	void remove(T e);
	int count() const;

	friend class aListAccessor<T>;
};

template<class T>
class aSingleList : public aList<T> {
protected:
	virtual int check(const T e) const;
	virtual int compareItems(const T& e1, const T& e2) const =0;
public:
	aSingleList() : aList<T>() {}
	virtual ~aSingleList() {};
};

template<class T>
class aListAccessor {
	aList<T> *theList;
	aList<T>::aListElement *current;
public:
	aListAccessor(aList<T>& l);
	aListAccessor(aList<T>* l);
	virtual ~aListAccessor();

	void first();
	void last();

	T get();
	int next();
	int prev();
	void deletecurrent();
        T removecurrent();
	void insertbefore(T e);
};

#endif