Program of Linked List Insertion and Deletion Operations in java

Linkedlist as we all know is one of the most important topic of interview especially for coding round.

We will not talk more about the theoretical part of linked list

Program for the insertion and deletion operation of linkedlist.

	public class LinkedList{
	Node head;
	Node current;
	public static class Node{
	int data;
	Node next;
	Node(int d){
	data =d; next=null;
	}
	}
	// insert at the fr=ont of the linkedlist
	public void insertAtFirst(int d){
	if(head ==null)
	{
	head = new Node(d);
	// return true;
	}
	else{
	Node n = new Node(d);
	n.next =head;
	head =n;
	}
	// return false;
	}
	public void insertAfter(int n1,int d){
	Node temp =head;
	while(temp!=null){
	if(temp.data==n1){
	Node n =new Node(d);
	n.next =temp.next;
	temp.next =n;
	break;
	}else{
	temp=temp.next;
	}
	}
	}
	public void insert(int d){
	if(head==null)
	{
	System.out.println("out");
	head =new Node(d);
	current =head;
	// return true;
	}else{
	System.out.println("in ");
	Node n = new Node(d);
	current.next=n;
	current=current.next;
	// return true;
	}
	}
	public void delete(int d){
	Node currentNode=head;
	Node previousNode=null;
	if(head.data ==d){
	head = head.next;
	}else{
	while(currentNode!=null){
	if(currentNode.data==d){
	previousNode.next=currentNode.next;
	break;
	}else{
	previousNode=currentNode;
	currentNode =currentNode.next;
	}
	}
	}
	}
	public void show(){
	System.out.println("---Showing---");
	Node myNode =head;
	while(myNode!=null){
	System.out.println(myNode.data);
	myNode =myNode.next;
	}
	}
	// delete linkedlist at a given position
	public void deleteAtPosition(int d){
	Node temp =head;
	Node prev =null;
	int count=1;
	if(d==1){
	head =head.next;
	}else{
	while(temp!=null)
	{
	if(count==d){
	prev.next=temp.next;
	break;
	}else{
	prev =temp;
	temp =temp.next;
	count++;
	}
	}
	}
	}
	}

view raw LinkedList.java hosted with ❤ by GitHub

In my earlier post I have talked about Tower of Hanoi problem 
You can also see other Sorting program
Bubble Sort 
Selection Sort
Insertion Sort 

Main Class File

	class LinkedListOperations {
	public static void main(String[] args) {
	LinkedList list = new LinkedList();
	list.insert(1);
	list.insert(2);
	list.insert(4);
	list.insert(3);
	list.insert(5);
	list.show();
	list.delete(2);
	list.delete(4);
	list.show();
	list.insertAtFirst(9);
	list.show();
	list.insertAfter(3,4);
	list.show();
	list.insertAfter(5,6);
	list.show();
	list.deleteAtPosition(3);
	list.show();
	list.deleteAtPosition(1);
	list.show();
	}
	}

view raw LinkedListOperations.java hosted with ❤ by GitHub

Hope this will help you in understand the program , Let me knowif you guys facing any problem in understanding this .


Thanks for reading.
-Noeik