Create LinkedLinkApp.java for hacktober2021

Program's_Contributed_By_Contributors/Java_Programs/LinkedLinkApp.java

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+package packageDA;
+
+//හැම node එකක්ම node class එකේ object එකක්. 
+//Head එකක් ඕනෙ පලවෙනි නෝඩ් එක හොයාගන්න 
+//Head පලවෙනි නෝඩ් එකේ ඔබ්ජෙක්ට් රෙෆෙරෙනස් එක. 
+//නෝඩ් ක්ලාස් එකේ දේවල් දෙකයි. 
+//එකක් තමන්ගෙ ඩේට එක තියාගන්න int data;  --> අනික,
+//හැම නෝඩ් එකක්ම එකම ටයිප් එකේ ඔබ්ජෙක්ට් එකකට රෙෆරන්ස් එකක් තියාගන්නව. Node next; 
+public class LinkedListApp {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+
+	}
+
+}
+//-------------------------------------
+//Node class
+class Node {
+	 int data;
+	 Node next;
+
+//constructor of node class
+	 Node(int item) {
+		 this.data=item;
+		 this.next=null;
+	 }
+
+//Display the node data
+	 void displayNode() {
+	  System.out.print(this.data + " ");
+	 } 
+	}
+//------------------------------------------
+
+// LinkedList Class
+	class LinkList {
+
+	 private Node head;
+
+//constructor
+	 public void LinkList() {
+	 head = null;
+	 }
+
+
+	 public boolean isEmpty() {
+		 return (this.head==null); 
+	 }
+
+// Add new node --> mulatamai new node set wenne. 
+//mechchara welaa head eke thibba value eka wenas wennna one aluth node eke object reference eka widihata.
+//aluth node ekee next variable ekata mechchara wela head eke thibba fereference eka ganna one.
+// ehemai aluth node eka link karanne
+	 public void insertFirst(int i) {
+		// create new node. Node(i) kiyla dena i value eka Constructor ekata gihin data kiyana ekata add wenawa 
+		 Node newNode = new Node(i);
+		 newNode.next =head;
+		 head = newNode;
+
+	 }
+
+// palaweni eka delete karanawa kiyanne head eka dewani node eke object referrence eka widihata set karanwa. ethakota palaweni node eka unlink wenawa.
+// aluth head eka wenne danata thiyana head eke next eka. Head = Head.next	 	 
+//delete krapu eka return krl pennanna nam ek issell temp ekk dagnn one delete krnn klin	
+	 public Node deleteFirst() {
+		 if(isEmpty()) {
+			 System.out.println("List is Empty , Nothing to delete");
+		 }
+		 Node temp = head;
+		 head = head.next;
+		 temp.next = null;
+		 return temp;
+
+	 }
+
+	 public void displayList() {
+		 if(isEmpty()) {
+			 System.out.println("List is empty, Nothing to diplay");
+		 }
+		 Node current = head;
+		 while(current != null) {
+			 current.displayNode();
+			 current = current.next;
+		 }
+		 System.out.println();
+	 }
+
+
+	 public Node find(int key) {
+		 Node current =head;
+		 int count =1;
+		 while(current!=null) {
+			 if(count==key) {
+				 return current;
+
+			 }
+			 current =current.next;
+			 count++;
+		 }
+		 System.out.println("Item not Found");
+		 return null;
+	 }
+
+	 public void delete(int key) {
+
+	        Node curr = this.head;
+	        Node prev = this.head;
+	        int count = 1;
+
+	        while(curr!=null){
+
+	            if(count == key){
+	                if(count == 1){
+	                    this.deleteFirst();
+	                }else{
+	                    prev.next = curr.next;
+	                    curr.next = null;
+	                }
+	            }
+
+	            prev = curr;
+	            curr = curr.next;
+	            count++;
+	        }
+
+	 }
+
+} 
+
+
+