ExcLinkedlist.java

class Node {

    private String data;
	private Node next;

	public Node(String data) {
		this.data = data;
	}

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

	public void setNext(Node node) {
		this.next = node;
	}

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

	public Node getNext() {
		return this.next;
	}
}


class LinkedList {

    private Node head;
	private Node tail;

	public Node getHead() {
		return this.head;
	}

	public Node getTail() {
		return this.tail;
	}

	public void addAtEnd(String data) {
		Node node = new Node(data);

		if (this.head == null) {
			this.head = this.tail = node;
		} else {
			this.tail.setNext(node);
			this.tail = node;
		}
	}

	public void addAtBeginning(String data) {
		Node node = new Node(data);

		if (this.head == null) {
			this.head = this.tail = node;
		}

		else {
			node.setNext(this.head);
			this.head = node;
		}
	}

	public void display() {
		Node temp = this.head;

		while (temp != null) {
			System.out.println(temp.getData());
			temp = temp.getNext();
		}
	}

	public Node find(String data) {
		Node temp = this.head;

		while (temp != null) {
			if (temp.getData().equals(data))
				return temp;
			temp = temp.getNext();
		}
		return null;
	}

	public void insert(String data, String dataBefore) {
		Node node = new Node(data);

		if (this.head == null)
			this.head = this.tail = node;
		else {
			Node nodeBefore = this.find(dataBefore);
			if (nodeBefore != null) {
				node.setNext(nodeBefore.getNext());
				nodeBefore.setNext(node);
				if (nodeBefore == this.tail)
					this.tail = node;
			} else
				System.out.println("Node not found");
		}
	}

	public void delete(String data) {

		if (this.head == null)
			System.out.println("List is empty");
		else {
			Node node = this.find(data);

			if (node == null)
				System.out.println("Node not found");

			if (node == this.head) {
				this.head = this.head.getNext();
				node.setNext(null);

				if (node == this.tail)
					tail = null;
		    } 
		    else {
				Node nodeBefore = null;
				Node temp = this.head;
				while (temp != null) {
					if (temp.getNext() == node) {
						nodeBefore = temp;
						break;
				    }
				    temp = temp.getNext();
			    }

				nodeBefore.setNext(node.getNext());

				if (node == this.tail)
					this.tail = nodeBefore;
				node.setNext(null);
			}
		}
	}
}


public class LinkedListExercise {

    public static void main(String args[]) {
         
	    LinkedList linkedList = new LinkedList();
	    linkedList.addAtEnd("AB");
	    linkedList.addAtEnd("BC");
	    linkedList.addAtEnd("CD");
	    linkedList.addAtEnd("DE");
	    linkedList.addAtEnd("EF");

	    String elementToBeFound = "CD";
	    int position = findPosition(elementToBeFound, linkedList.getHead());
	    if (position != 0)
	        System.out.println("The position of the element is " + position);
	    else
	        System.out.println("The element is not found!");
	 }

	 public static int findPosition(String element, Node head) {
	    int position = 1;
        Node current = head;

        while (current != null) {
            if (current.getData().equals(element)) {
                return position;
            }
            current = current.getNext();
            position++;
        }

        // If element is not found
	    return 0;        
	 }
}