How to fix Linked List implementation problem?

Question

I'm think inserting values correctly also I can view on console screen however search method does not work at weird way

What is the missing all my code ? it pretty clear and basic structure

at the output part "43" normally include on structure it need to show true but probably it does not working I dont know reason. output: 43 43 33 43 13 3 check: false

 NodeList head;

    public void insert(int insertKey) {
        NodeList myhead = new NodeList();
        if (head == null) {
            myhead.setData(insertKey);
        } else {
            myhead.setData(insertKey);
            myhead.setLink(head);
           
        }
            head = myhead;
    }
    public boolean search(int key) {

        boolean check = false;
        NodeList current = head;
        while (current != null) {
            if (current.getData() == key) {
                check = true;
                break;
            }
            current = current.getLink();

        }
        return check;
    }

public void display() {
        if (head == null) {
        } else {
            while (head != null) {
                System.out.print(head.getData() + " ");
                head = head.getLink();
            }
            System.out.println();
        }
    }



package ds_project;

public class NodeList {

    private NodeList Link;
    private int data;

    public NodeList(int data) {
        this.Link = null;
        this.data = data;
    }

    public NodeList() {
    }


    public NodeList getLink() {
        return Link;
    }

    public void setLink(NodeList Link) {
        this.Link = Link;
    }

    public int getData() {
        return this.data;
    }

    public void setData(int data) {
        this.data = data;
    }

result screen
  SLL Linkedlist = new SLL();
        Linkedlist.insert(3);
        Linkedlist.insert(13);
        Linkedlist.insert(43);
        Linkedlist.insert(33);
        Linkedlist.insert(43);
        Linkedlist.insert(43);
        Linkedlist.display();
        boolean check=Linkedlist.search(43);
        System.out.println("check: " + check);}

output: 43 43 33 43 13 3 check: false

Answer 1

The display method is wrong, head will become the tail node. Use a temp node:

    public void display() {
        NodeList tmp = head;
        if (tmp != null) {
            while (tmp != null) {
                System.out.print(tmp.getData() + " ");
                tmp = tmp.getLink();
            }
            System.out.println();
        }
    }

Edit: my test code:

public class NodeList {

    private NodeList Link;
    private int data;

    public NodeList(int data) {
        this.Link = null;
        this.data = data;
    }

    public NodeList() {
    }


    public NodeList getLink() {
        return Link;
    }

    public void setLink(NodeList Link) {
        this.Link = Link;
    }

    public int getData() {
        return this.data;
    }

    public void setData(int data) {
        this.data = data;
    }

    NodeList head;

    public void insert(int insertKey) {
        NodeList myhead = new NodeList();
        if (head == null) {
            myhead.setData(insertKey);
        } else {
            myhead.setData(insertKey);
            myhead.setLink(head);

        }
        head = myhead;
    }
    public boolean search(int key) {

        boolean check = false;
        NodeList current = head;
        while (current != null) {
            if (current.getData() == key) {
                check = true;
                break;
            }
            current = current.getLink();

        }
        return check;
    }
    public void display() {
        NodeList tmp = head;
        if (tmp != null) {
            while (tmp != null) {
                System.out.print(tmp.getData() + " ");
                tmp = tmp.getLink();
            }
            System.out.println();
        }
    }

    public static void main(String[] args) {
        NodeList Linkedlist = new NodeList();
        Linkedlist.insert(3);
        Linkedlist.insert(13);
        Linkedlist.insert(43);
        Linkedlist.insert(33);
        Linkedlist.insert(43);
        Linkedlist.insert(43);
        Linkedlist.display();
        boolean check=Linkedlist.search(43);
        System.out.println("check: " + check);
    }

}