complete circular linklist but not remove last element.

Author: rajendrapancholi

.gitignore

@@ -1 +1,2 @@
-*.class
+*.class
+/.vscode/*

CircularlyLinkedList.java

@@ -1,6 +1,127 @@
-public class CircularlyLinkedList{
- 
+class CircularLikedList <E>{
+ //create a node
+ private static class Node<E> {
+ private E element;
+ private Node<E> next;
+ public Node (E e, Node<E> n){
+ element = e;
+ next = n;
+ }
+ public E getElement(){
+ return element;
+ }
+ public Node<E> getNext(){
+ return next;
+ }
+ public void setNext(Node<E> n){
+ next = n;
+ }
+ }
+ private Node<E> tail = null;
+ private int size = 0;
+ public void CircularLikedList() {}
+ //access methods
+ public int size(){return size;}
+ public boolean isEmpty(){return size == 0;}
+ public E getFirst(){
+ if (isEmpty()) {
+ return null;
+ }
+ return tail.getNext().getElement();
+ }
+ public E getLast(){
+ if (isEmpty()) {
+ return null;
+ }
+ return tail.getElement();
+ }
+ //update methods
+ public void rotate(){
+ if (tail != null) {
+ tail = tail.getNext();
+ }
+ }
+ public void addFirst(E e){
+ if (size == 0) {
+ tail = new Node<>(e, null);
+ tail.setNext(tail);
+ } else{
+ Node<E> newest = new Node<>(e, tail.getNext());
+ tail.setNext(newest);
+ }
+ size++;
+ }
+ public void addLast(E e){
+ addFirst(e);
+ tail = tail.getNext();
+ }
+ public E removeFirst(){
+ if (isEmpty()) {
+ return null;
+ }
+ Node<E> head = tail.getNext();
+ if (head == tail) {
+ tail = null;
+ }else{
+ tail.setNext(head.getNext());
+ }
+ size--;
+ return head.getElement(); 
+ }
+ public E removeLast(){
+ if (isEmpty()) {
+ System.out.println("Empty!");
+ return null;
+ }
+ if (tail.next==tail) {
+ tail = null;
+ return null;
+ }
+ Node<E> secondLast = tail;
+ Node<E> rmElem = tail;
+ while( secondLast.next != rmElem){
+ secondLast = secondLast.next;
+ tail = secondLast;
+ System.out.println("tail: "+tail.getElement());
+ }
+ remove(tail);
+ return rmElem.getElement();
+ }
+ public void display() {
+ if (tail == null) {
+ System.out.print("Circular Linked List is empty!");
+ return;
+ }
+ Node<E> temp = tail;
+
+ do{
+ System.out.print(temp.element + " ");
+ temp = temp.next;
+ } while (temp != tail);
+ System.out.println();
+ }
+
+}
+//main class
+public class CircularlyLinkedList<E>{
  public static void main(String[] args){
- // code here
+ CircularLikedList<Integer> cll = new CircularLikedList<>();
+ // cll.addFirst(5);
+ // cll.addFirst(4);
+ // cll.addFirst(3);
+ cll.addFirst(2);
+ cll.addFirst(1);
+ cll.addLast(3);
+ System.out.println("First Element: "+cll.getFirst());
+ System.out.println("Last Element: "+cll.getLast());
+ System.out.println("Total Element: "+cll.size());
+ cll.display();
+ System.out.println("remove Last Element: "+cll.removeLast());
+ // String remove = "Removed element: "+cll.removeFirst();
+ // System.out.println("After remove first element.");
+ System.out.println("Total Element: "+cll.size());
+ // System.out.println(remove);
+ cll.display();
+ 
  }
 }

SignlyLinkedList.java

@@ -7,7 +7,7 @@ public void SignlyLinkedList(){}
  public int size(){return size;}
  public boolean isEmpty() {return size==0;}
 
- public static class Node<E> {
+ private static class Node<E> {
  private E element;
  private Node<E> next;
  public Node (E e, Node<E> n){