circular.java

public class circular {
    class solution{
        static class Node{
            int data;
            Node next;
        }
        static Node addToEmpty(Node last , int data){
            if(last!=null){
                return last;
            }
            Node newNode = new Node();
            newNode.data = data;
            last = newNode;
            newNode.next = last;
            return last;

        }
        static Node addToFront(Node last, int data){
            if(last==null){
                return addToEmpty(last, data);
            }
            Node newNode = new Node();
            newNode.data = data;
            newNode.next = last.next;
            last.next = newNode;
            return last;

        }
        static Node addEnd(Node last,int data){
            if(last==null){
                return addToEmpty(last, data);
            }
            Node newNode = new Node();
            newNode.data = data;
            newNode.next = last.next;
            last.next = newNode;
            last = newNode;
            return last;
        }
        static Node addafter(Node last,int item,int data){
            if(last == null){
                return null;

            }
            Node newNode, p;
            p = last.next;
            do{
                if(p.data == item){
                    newNode = new Node();
                    newNode.data = data;
                    newNode.next = p.next;
                    p.next = newNode;
                    if(p==last){
                        last =newNode;

                    }
                    return last;

                }
                p =p.next;
            }while(p!=last.next);
            System.out.println(item+ "the gnis not present");
            return last;

        }
        static Node deleteNode(Node last,int key){
            if(last == null){
                return null;
            }
            if(last.data == key&&last.next == last){
                last = null;
                return last;
            }
            Node temp = last,d=new Node();
            if(last.data == key){
                while(temp.next!=last){
                    temp= temp.next;
                }
            }
            while(temp.next!=last&&temp.next.data !=key){
                last = temp.next;
            }
            if(temp.next.data == key){
                d = temp.next;
                temp.next = d.next;
            }return last;

            
        }
        static void printcll(Node last) {
            Node p;
            if (last == null) {
                System.out.println("List is empty.");
                return;
            }
            p = last.next;
            do {System.out.print(p.data + " ");
                p = p.next;
            }while (p != last.next);
        }
        
        public static void main(String[] args) {
            Node last = null;
            last = addToEmpty(last, 6);
            last = addEnd(last, 8);
            last = addToFront(last, 2);
            last = addafter(last, 10, 2);
            printcll(last);
            deleteNode(last, 8);
            printcll(last);}
        

    }
    
}