Linked List Implementation

Linked List Impl in Java

public class Node {

            private int data;

            private Node nextNode;

            public Node(int data){

                        this.data=data;

            }

           

            public int getData() {

                        return data;

            }

           

            public void setData(int data) {

                        this.data = data;

            }

           

            public Node getNextNode() {

                        return nextNode;

            }

           

            public void setNextNode(Node nextNode) {

                        this.nextNode = nextNode;

            }

           

            @Override

            public String toString(){

                        return ""+this.data;

            }

}

           

public class LinkedList {

            public Node head;

            public Node reverseLinkedList(Node currentNode) {

                        // For first node, previousNode will be null

                        Node previousNode = null;

                        Node nextNode;

                        while (currentNode != null) {

                                    nextNode = currentNode.getNextNode();

                                    // reversing the link

                                    currentNode.setNextNode(previousNode);

                                    // moving currentNode and previousNode by 1 node

                                    previousNode = currentNode;

                                    currentNode = nextNode;

                        }

                        return previousNode;

            }

            public void add(int data) {

                        if (head == null)

                                    insertAtHead(data);

                        else

                                    insertAtEnd(data);

            }

            public void insertAtHead(int data) {

                        Node newNode = new Node(data);

                        newNode.setNextNode(this.head);

                        this.head = newNode;

            }

            public int length() {

                        Node current = this.head;

                        int count = 0;

                        while (current != null) {

                                    current = current.getNextNode();

                                    count++;

                        }

                        return count;

            }

            public void deleteAtHead() {

                        this.head = this.head.getNextNode();

            }

            public String find(int data) {

                        Node current = this.head;

                        while (current != null) {

                                    if (current.getData() == data)

                                                return data + " Found";

                                    current = current.getNextNode();

                        }

                        return data + " Not Found ";

            }

            public void insertAfterData(int dataPresent, int dataAdd) {

                        Node current = this.head;

                        while (current != null) {

                                    if (current.getData() == dataPresent) {

                                                Node newNode = new Node(dataAdd);

                                                newNode.setNextNode(current.getNextNode());

                                                current.setNextNode(newNode);

                                                break;

                                    }

                                    current = current.getNextNode();

                        }

            }

            public void insertBeforeData(int dataPresent, int dataAdd) {

                        Node current = this.head;

                        while (current != null) {

                                    if (current.getNextNode().getData() == dataPresent) {

                                                Node newNode = new Node(dataAdd);

                                                newNode.setNextNode(current.getNextNode());

                                                current.setNextNode(newNode);

                                                break;

                                    }

                                    current = current.getNextNode();

                        }

            }

            public void insertAtEnd(int dataAdd) {

                        Node current = this.head;

                        while (current.getNextNode() != null) {

                                    current = current.getNextNode();

                        }

                        Node newNode = new Node(dataAdd);

                        newNode.setNextNode(current.getNextNode());

                        current.setNextNode(newNode);

            }

            public void deleteNode(int dataPresent) {

                        Node current = this.head;

                        while (current != null) {

                                    if (current.getNextNode().getData() == dataPresent) {

                                                current.setNextNode(current.getNextNode().getNextNode());

                                                break;

                                    }

                                    current = current.getNextNode();

                        }

            }

            @Override

            public String toString() {

                        String result = "{";

                        Node current = this.head;

                        while (current != null) {

                                    result += current.toString() + "-->";

                                    current = current.getNextNode();

                        }

                        result += "null }";

                        return result;

            }

}

public class LinkedNodeDemo {

            public static void main(String[] args) {

                        LinkedList list = new LinkedList();

                        list.insertAtHead(10);

                        list.insertAtHead(20);

                        list.insertAtHead(15);

                        list.insertAtHead(25);

                        list.insertAtHead(40);

                        System.out.println("List after insertAtHead Operation" + list);

                        System.out.println("Length is " + list.length());

                        list.deleteAtHead();

                        System.out.println("List after deleteAtHead Operation" + list);

                        System.out.println(list.find(100));

                        list.insertAfterData(20, 12);

                        System.out.println("List after insertAfterData Operation " + list);

                        list.insertBeforeData(20, 6);

                        System.out.println("List after insertBeforeData Operation" + list);

                        list.insertAtEnd(19);

                        System.out.println("List after insertAtEnd Operation" + list);

                        list.deleteNode(20);

                        System.out.println("List after deleteNode Operation" + list);

                       

                        LinkedList list1 = new LinkedList();

                        list1.add(10);

                        list1.add(20);

                        list1.add(20);

                        System.out.println(list1);

            }

}

Output :

List after insertAtHead Operation{40-->25-->15-->20-->10-->null }

Length is 5

List after deleteAtHead Operation{25-->15-->20-->10-->null }

100 Not Found

List after insertAfterData Operation {25-->15-->20-->12-->10-->null }

List after insertBeforeData Operation{25-->15-->6-->20-->12-->10-->null }

List after insertAtEnd Operation{25-->15-->6-->20-->12-->10-->19-->null }

List after deleteNode Operation{25-->15-->6-->12-->10-->19-->null }

New List is(Like Build-In) {10-->20-->20-->null }

Pictorial representation of LinkedList