// Copyright (C) 1996 DIMACS Center, Rutgers, The State University of New Jersey
// Author(s): ??, Jonathan Berry

// This software is copyrighted by the DIMACS Center at Rutgers, The State
// University of New Jersey.  IT IS PROVIDED AS IS, AND THE AUTHORS, DIMACS, AND
// RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY  DISCLAIM
// ALL LIABILITY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
// DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

// THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
// IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
// NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
// MODIFICATIONS.

// The authors hereby grant permission to use, copy, modify, distribute,
// and license this software and its documentation for any purpose, provided
// that existing copyright notices are retained in all copies and that this
// notice is included verbatim in any distributions. No written agreement,
// license, or royalty fee is required for any of the authorized uses.
// Modifications to this software may be copyrighted by their authors
// and need not follow the licensing terms described here, provided that
// the new terms are clearly indicated on the first page of each file where
// they apply.

// Last File Update: 31-Jul-1996
// 

#ifndef Deque_h
#define Deque_h

#include <LINK/basic/List.h>


template <class Item>
class Deque : private List<Item> {
protected:
    void		copy(const Deque&);
public:
    Deque() {}
    ostream&		display(ostream& os) const;
    Item		front();
    virtual void	insert(Item&) = 0;
    void		clear();     
    Item		get();
    void		insertFirst(Item&);
    void		insertLast(Item&);
    Bool		emptyQ();
    virtual Bool        operator==(const Deque<Item>&) const;
    virtual Bool        operator<=(const Deque<Item>&) const;
    virtual Bool        operator<(const Deque<Item>&)  const;
    virtual Bool        operator>=(const Deque<Item>&) const;
    virtual Bool        operator>(const Deque<Item>&) const;
    virtual Bool        operator!=(const Deque<Item>&) const;
    friend ostream& operator<<(ostream&, const Deque<Item>&);
};


#ifdef DEFINE_TEMPLATE
#include <LINK/basic/Deque.cc>
#endif

#endif