Sagar

public class SinglyLinkedListPractice {
Node head;
//creating of Node in Singly linked list
class Node
{
String data;
Node next;

Node(String data)
{
this.data=data;
this.next=null;
}
}
//Add fist operation
public void addFirst(String data){
Node newNode=new Node(data);
if (head==null){
head=newNode;
return;
}
newNode.next=head; // set the newNode.next as a head
head=newNode; // Now the head is point to the newNode
}

//Add Last operation
public void addLast(String data){
Node newNode=new Node(data);
if (head==null)
{
head=newNode;
return;
}
Node currNode=head;
while (currNode.next != null)
{
currNode=currNode.next; //upadate the current node as a next node till currNode.next == null
}
currNode.next=newNode;
}
//Print operation of sll
public void printList()
{
if (head==null)
{
System.out.println(“The linked list is empty”);
return;
}
Node currNode=head;
while (currNode != null)
{
System.out.print(currNode.data+” -> “);
currNode=currNode.next;
}
System.out.println(“NULL”);
}
//Check the size of Linked list
public int checkSize()
{
if (head==null)
{
System.out.println(“The linked list empty”);
}
Node currNode=head;
int count=0;
while (currNode.next != null)
{
count++;
currNode=currNode.next;
}
return count;
}

//insertion at specific position
public void insertSpecific(String data,int position)
{
Node newNode=new Node(data);
if (position checkSize())
{
System.out.println(“Invalid position”);
}
Node currNode=head;
int i=0;
while (i<position)
{
currNode=currNode.next;
i++;
}
if (i==position)
{
newNode.next=currNode.next;
currNode.next=newNode;
}
}

public static void main(String[] args) {
SinglyLinkedListPractice sll=new SinglyLinkedListPractice();
sll.addFirst("10");
sll.addFirst("20");
sll.printList();
sll.addLast("30");
sll.printList();
sll.addFirst("40");
sll.printList();
sll.insertSpecific("50",1);
sll.printList();
}
}