/** ADT deque interface

@file DequeInterface.h */

#ifndef _DEQUE_INTERFACE

#define _DEQUE_INTERFACE

template<class ItemType>

class DequeInterface

{

	/** Checks to see if deque is empty

	@pre None.

	@return True if empty, false if not */

	virtual bool empty() const = 0;

	/** Insert a new entry into the front of deque

	@post newEntry is at the

	front of the deque, if the operation is succesful.

	@param newEntry The object to be added as a new entry.

	@return Returns true if addition is successful, otherwise false */

	virtual bool addFront(const ItemType& newEntry) = 0;

	/** Adds a new entry to the back of this deque.

	@post If successful, newEntry is at the

	back of the deque.

	@param newEntry The object to be added as a new entry.

	@return True if the addition is successful or false if not. */

	virtual bool addBack(const ItemType& newEntry) = 0;

	/** Removes the front of this deque.

	@post If the operation was successful, the front of the deque

	has been removed.

	@return True if the removal is successful or false if not. */

	virtual bool removeFront() = 0;

	/** Removes the back of this deque.

	@post If the operation was successful, the front of the deque

	has been removed.

	@return True if the removal is successful or false if not. */

	virtual bool removeBack() = 0;


		/** Returns the front of this deque.

		@pre The deque is not empty.

		@post The front of the deque has been returned, and the

		deque is unchanged.

		@return The front of the deque. */

		virtual ItemType peekFront() const = 0;



	/** Returns the back of this deque.

	@pre The deque is not empty.

	@post The back of the deque has been returned, and the

	deque is unchanged.

	@return The back of the deque. */

	virtual ItemType peekBack() const = 0;

} // end DequeInterface

#endif