Implementing methods in Custom Linked List using Java

Question

I am currently doing a programming project myself and I require some help.

This is the LinkedList class I am using:

class LinkedList {
    Node cursor;
    private Node head;  // first node in the linked list
    private int count;

    public int getCount() {
        return count;
    }
    public Node getHead() {
        return head;
    }
    public LinkedList() {
        head = null;    // creates an empty linked list
        count = 0;
    }
    public void addFront(int n) {
        Node newNode = new Node(n);
        newNode.setLink(head);
        head = newNode;
        count++;
    }
    public void deleteFront() {
        if (count > 0) {
            Node temp = head;
            head = temp.getLink();
            temp = null;
            count--;
        }
    }
}

Below are my questions:

How do I create a method to remove a node in the LinkedList at any position? Assuming that the first node has the position of 1, second node has the position of 2 and so on and so forth.
How do I swap the position of nodes for lets say node 1 and node 2?
How do I sort the LinkedList based on the name in ascending order (assuming the name is 'albumName')?

I'm using a linkedlist class that I found online. Do i need to paste the codes down? — Deon
– Deon, Commented Jan 1, 2013 at 1:11
If you want help with code, it will always help to post the code. — Don Roby
– Don Roby, Commented Jan 1, 2013 at 1:16
Don't use the "linked list class that you found online" if you can use the standard "java.util.LinkedList" instead! IMHO... — paulsm4
– paulsm4, Commented Jan 1, 2013 at 2:19

Jake Varness · Accepted Answer · 2013-01-01 01:09:24Z

1.) You have to write some sort of find(int) method that returns a Node that will allow you to get a reference to the node you're looking to remove.

Assuming you have a doubly-linked one, you can just change the references of the nodes around and the garbage collector will clean that node out of memory.

If it's signly-linked, you need to use a for loop that will find the node you want to remove, then, using a reference to the previous node that follows the current one, change the reference of next in prev to be curr.next.

2.) If you write a find method, you can either switch the data in the nodes, or you can use similar for loops from your remove to change the references of the nodes around.

3.) Write a selection sort using nodes that will sort the data. Nodes don't need to necessarily be moved around, you could probably just switch the data.

for(Node curr = this.head; curr != null; curr = curr.next)
    for(Node next = curr.next; next != null; next = next.next)

Something like that.

paulsm4 · Accepted Answer · 2013-01-01 00:54:01Z

0

I assume you're using the standard Java "Linked List" collection, and not implementing your own.

If so, all you have to do is look at the Javadoc and/or any number of fine tutorials on Java collections.

For example:

answered Jan 1, 2013 at 0:54

paulsm4

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1 Comment

Deon Over a year ago

Thanks for you input. But I am quite confuse by the tutorial because they are implementing in the main class. What i need to do is add the methods into the linkedlist class and not the main. Thanks!

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