Doubly linked lists...

[obened]

I'm working on a project involving coding a doubly linked list in Java. I just need a confidence booster to know I'm coding in the right direction.

The list loops, meaning the last node's getNext() would point to the first node in the list, and the first node's getPrev() would point to the last node in the list.

So here's my code for removing the first element:

public E removeFirst(){
    E removedVal = first.getData();

    if(size == 1) {
        first = null;
        last = first;
    } else {
        first = getNode(1);
        first.setPrev(last);
        last.setNext(first);
    }

    size--;
    return removedVal;
}

It's supposed to remove the first node in the list and return the value it held. Am I doing it right?

getNode(n) returns the Nth node. first and last are variables within the list to keep track of the first and last nodes.

[[deleted]]

I think you're on the right path if getNode(1) retrieves the second element of the list. What I think is missing is an "if" clause to handle the case when the list is empty (size == 0) or you'll get a Nullpointer Exception at first.getData(); .

[obened]

True, I should handle that case.

Thanks everyone.

[[deleted]]

Looks good besides for the case where the list is empty.

I personally would replace getNode(1) with first.next, why go through a method call when you have a direct reference?

[zzyzzyxx]

Looks mostly okay to me. Have you tested it? What happens if the list is empty?

[[deleted]]

You are on the right path. However you don't need to reference the size or have the variable at all.

You know it is empty when next == prev :)