public class SinglyLinkedList {

class Node{

int data;

Node next;

Node(int data){

this.data=data;

this.next=null;

}

}

Node head=null;

Node tail=null;

int size;

void addNode(int data) {

Node n=new Node(data);

if(head==null) {

head=n;

tail=n;

}

else {

tail.next=n;

tail=n;

}

size++;

}

public int size() {

return size;

}

public int count() {

int c=0;

Node current=head;

while(current!=null) {

c++;

current=current.next;

}

return c;

}

void insertAtBegin(int data) {

Node n=new Node(data);

if(head==null) {

head=n;

}

else {

Node temp=head;

head=n;

n.next=temp;

}

}

void insertAtEnd(int data) {

Node n=new Node(data);

if(head==null) {

head=n;

tail=n;

}

else {

tail.next=n;

tail=n;

}

}

void insertAtPostion(int data,int idx) {

Node n=new Node(data);

Node temp=head;

if(head==null) {

head=n;

tail=n;

}

for(int i=0; i<idx-1; i++) {

temp=temp.next;

}

n.next=temp.next;

temp.next=n;

}

void insertAtmid(int data) {

int count=size%2;

Node n=new Node(data);

Node temp=head;

if(head==null) {

head=n;

tail=n;

}

for(int i=0; i<count-1; i++) {

temp=temp.next;

}

n.next=temp.next;

temp.next=n;

}

void display() {

Node cur=head;

while(cur!=null) {

System.out.print(cur.data+",");

cur=cur.next;

}

System.out.println();

}

public static void main(String[] args) {

SinglyLinkedList s1=new SinglyLinkedList();

s1.addNode(10);

s1.addNode(20);

s1.addNode(30);

s1.addNode(40);

s1.display();

System.out.println(s1.count());

System.out.println(s1.size());

System.out.println("After Inserting the Element At the Begining");

s1.insertAtBegin(100);

s1.display();

System.out.println("After Inserting the Elements At the End");

s1.insertAtEnd(200);

s1.display();

System.out.println("Insert at Any position");

s1.insertAtPostion(500,3);

s1.display();

System.out.println("After Inserting the Elements At The Middle Of the List");

s1.insertAtmid(1000);

s1.display();

}

}