CODEWITHSUNDEEP
javaarrayslinked-listdoubly-linked-list
kevinsangabriel
kevinsangabriel

Reputation: 9

Implementing a remove method for a doubly linked list

I'm trying to implement a doubly linked list for a class assignment. I am currently stuck on implementing a method to remove a node at a specified index. 

public void remove(int index) {
    if (index < 0 || index > count-1) {
        throw new ListIndexOutOfBoundsException("The index "+index+" is out of bounds.");
    }
    if (isEmpty()) {
        System.out.println("List is empty");
        return;
    }

    MedicationNode curr = head;
    int k = 0;
    while(k < index) {
        curr = curr.next;
        k++;
    }
    if (curr.prev == null) {
        curr.next.prev = null;
    }else if(curr.next == null) {
        curr = curr.prev;
        curr.next = null;
    }else{
        curr.next.prev = curr.prev;
        curr.prev.next = curr.next;
    }           
    count--;
}

the method can remove any specified node in a linked list except index 0. I'm thinking the problem may be with my add method but im not really sure.

Upvotes: 0

Views: 972

Answers (1)

Jyotman Singh
Jyotman Singh

Reputation: 11330

In your first if condition - 

if (curr.prev == null) {
    curr.next.prev = null;
    //Make your head of the linked list point to this node
    head = curr.next;
}

This is because you are removing the head from the list so the head should point to the head's next node.

Upvotes: 1

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