CODEWITHSUNDEEP
javalinked-list
Breanna Burgess
Breanna Burgess

Reputation: 45

Java- Print doubly linked list in reverse

I am trying to print a doubly linked list starting with the tail element and ending with the first. My current code below does that but is also returning the dequed items for some reason. When I print the list from the head to the tail, it doesn't do this. Idk if it's the toString causing this or the dequed methods. I have included both.

public String toString() {

    String result;

    if (isEmpty())
        return "empty";
    else {
        result = "";
        DoubleNode current = tail;

        while (current != null) {
            result = result + current.getElement() + " ";
            current = current.getPrev();
        }
    }
    return result;
}


public Item dequeueBack() throws NoSuchElementException {
    if (isEmpty())
        throw new NoSuchElementException("deque is empty");

    Item result = tail.getElement();
    tail = tail.getPrev();
    count--;

    if (isEmpty())
        head = null;
    else
        tail.setNext(null);

    return result;
}

Upvotes: 0

Views: 429

Answers (1)

Scott Hunter
Scott Hunter

Reputation: 49803

You don’t setPrev anything when you dequeue, so those links (which you print is based on) still work.

Upvotes: 1

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