LinkedList All operations JAVA !!

 

package Linkedlist;

public class linkedlist1 {
    Node head;
    class Node{
        int data;
        Node next;

        Node(int data){//constructor
            this.data=data;
            this.next=null;
        }
    }
    //add first
public void addfirst(int data){
        Node newNode=new Node(data);
        if(head==null){
            head=newNode;
            return;
        }
        newNode.next=head;
        head=newNode;
}
//addlast
public void addLast(int data){
    Node newNode=new Node(data);
    if(head==null){
        head=newNode;
        return;
    }
    Node currNode=head;
    while (currNode.next!=null){
        currNode=currNode.next;
    }
    currNode.next=newNode;

}
//print the linkedlist
public void printList(){
        if(head==null){
            System.out.println("list is empty ");
            return;
        }
        Node currNode=head;
        while (currNode!=null){
            System.out.print(currNode.data+" - ");
            currNode=currNode.next;
        }
    System.out.println("null");
}

//delete operations
    //delete first
    public void delfirst(){
        if(head==null){
            System.out.println("the list is empty");
            return;
        }
        head=head.next;
    }
    //delete last element from the linked list
    
public void dellast(){
    if(head==null){
        System.out.println("the list is empty");
        return;
    }
    if(head.next==null){
        head=null;
        return;
    }
    Node secondlast=head;
    Node lastnode=head.next;
    while (lastnode.next!=null){
        lastnode=lastnode.next;
        secondlast=secondlast.next;
    }
    secondlast.next=null;
}

    public static void main(String[] args) {
        linkedlist1 list=new linkedlist1();
//        list.addfirst(78);
////        list.addfirst("a");
        list.addLast(90);
        list.addLast(91);
        list.addLast(92);
        list.printList();
        list.delfirst();
        list.dellast();
        list.printList();

    }
}