//DISPLAY 13.21 Interface File for a Queue Class
//This is the header file queue.h. This is the interface for the class Queue,
//which is a class for a queue of symbols.
#ifndef QUEUE_H
#define QUEUE_H
namespace queuesavitch
{
    struct QueueNode
    {
        char data;
        QueueNode *link;
    };

    typedef QueueNode* QueueNodePtr;

    class Queue
    {
    public:
        Queue( );
        //Initializes the object to an empty queue.

        Queue(const Queue& aQueue);

        ~Queue( );



void add(char item);
        //Postcondition: item has been added to the back of the queue.

        char remove( );
        //Precondition: The queue is not empty.
        //Returns the item at the front of the queue and
        //removes that item from the queue.

        bool empty( ) const;
        //Returns true if the queue is empty. Returns false otherwise.
    private:
        QueueNodePtr front;//Points to the head of a linked list.
                            //Items are removed at the head
        QueueNodePtr back;//Points to the node at the other end of the
                           //linked list. Items are added at this end.
    };
}//queuesavitch
#endif //QUEUE_H