Question

There seems to be an issue with my dequeue function within a queue class that I have. My dequeue function which is part of the position class, is not returning the correct values that have been enqueued into the list.

The values that have been enqueued are which is a position object, are 2,1 and -1, but when I dequeue that object i get 2,506216, and -1; When I assign the *pos ponter to an object I am left with the default values;The enqueue function seems to be working correctly for when I check the ptr values they are correct.

//position constructor
front = back = &header;

        struct Posnode
        {   
           Position *pos;
           Posnode *next;    
        };
    class Position
    private:
              Posnode *front,*back,header;
void Position::dequeue(Position&p)
{
    Posnode *ptr=front->next;
    front->next = ptr->next;
    p = *ptr->pos;
    p.geta();//checking for values but am left with the default

    if (back == ptr)
    {
        back = front;
    }
    delete ptr;

}
v

oid Position::enqueue(Position n) //assigning Position object to end of queue
    {
        Posnode *ptr = new Posnode;
        ptr-> pos =  &n;
        back->next = ptr;
        back = ptr;

        return;
    }

Position copy,intial(5);
copy = intial;

        if (copy.ismovelegal(posmoves, r))
        {
            copy.makemove(posmoves, r);


            if (intial.solved(copy))
            {
                cin.get();
            }
            else
            {
                p.enqueue(copy);


            }
        }
        copy.free();//clearing object private memebers
    }
    intial.free();

    p.dequeue(o);//copy that was previous enqued is not enqued
    o.geta();

Answer 1

Just Check out the Implementation of Deque first and then try your own. If its some syntax or semantic error post minimal code that reproduces your code.

this link might help you. Deque Implementation