DoubleLinkedList

package linkedlist;

import java.util.Scanner;

public class DoublyLinkedList {
    public static void main(String[] args) {
        DoublyLinkedList2 list = new DoublyLinkedList2();
        Scanner sc = new Scanner(System.in);
        String[] menu = { "Doubly Linked List Operations", "[1] - Add to Head", "[2] - Add to Tail ",
                "[3] - Add an Item after the target", "[4] - Remove From Head ", "[5] - Remove from Tail",
                "[6] - Remove the target item", "[7] - Print Head", "[8] - Print Tail", "[9] - Print Forward",
                "[10] - Print Backward", "[0] - Exit" };
        int choice = 0;
        do {
            for (String menuPrint : menu) {
                System.out.println(menuPrint);
            }
            System.out.print("Enter the number of your choice: ");
            choice = sc.nextInt();

            switch (choice) {
                case 1:
                    System.out.print("Enter number to add to head: ");
                    list.addToHead(sc.nextInt());
                    break;
                case 2:
                    System.out.print("Enter number to add to tail: ");
                    list.addToTail(sc.nextInt());
                    break;
                case 3:
                    System.out.print("Enter number to insert: ");
                    int insertNumeber = sc.nextInt();
                    System.out.print("Enter number of target position to insert: ");
                    int targetPosition = sc.nextInt();
                    // list.addToTail(sc.nextInt());
                    break;
                case 4:
                    list.deleteHead();
                    break;
                case 5:
                    list.deleteTail();
                    break;
                case 6:
                    System.out.print("Enter number of target position to remove: ");
                    int targetRemove = sc.nextInt();
                    list.deletTarget(targetRemove);
                    break;
                case 7:
                    list.printHead();
                    break;
                case 8:
                    list.printTail();
                    break;
                case 9:
                    list.printForward();
                    break;
                case 10:
                    list.printBackward();
                    break;
                case 0:
                    System.out.println("Exited...");
                    break;
            }
        } while (choice != 0);

    }
}

//Other files

package linkedlist;

//doubly linked list file

public class DoublyLinkedList2 {
    Node head;
    Node tail;

    public DoublyLinkedList2() {
        head = tail = null;

    }

    public DoublyLinkedList2(Node head, Node tail) {
        this.head = head;
        this.tail = tail;
    }

    public boolean isCget() {
        return head == null && tail == null ? true : false;
    }

    public void addToHead(int item) {
        if (isCget()) {
            Node newNode = new Node(null, item, null);
            head = tail = newNode;
        }

        else {
            Node newNode = new Node(null, item, head);
            head = newNode;
            head.next.previous = head;
        }
    }

    public void addToTail(int item) {
        if (isCget()) {
            Node newNode = new Node(null, item, head);
            tail = head = newNode;
        }

        else {
            Node newNode = new Node(null, item, head);
            tail = newNode;
            tail.next.previous = tail;
        }
    }

    public void printHead() {
        System.out.println("Head: " + head.item);
    }

    public void printTail() {
        System.out.println("Tail: " + tail.item);
    }

    public void printForward() {
        Node current;
        current = head;
        System.out.println("Printing Forward");
        while (current != null) {
            System.out.print(" " + current.item);
            current = current.next;

        }
        System.out.println("");
    }

    public void printBackward() {
        Node current;
        current = tail;
        System.out.println("Printing Backward");
        while (current != null) {
            System.out.print(" " + current.item);
            current = current.previous;

        }
        System.out.println("");
    }

    public void deleteHead() {
        if (this.head != null) {
            Node temp = this.head;
            this.head = this.head.next;
            temp = null;
            if (this.head != null)
                this.head.previous = null;
        }
    }

    // Delete last node of the list
    public void deleteTail() {
        int item = 0;
        if (this.head != null) {
            if (this.head.next == null) {
                this.head = null;
            } else {
                Node temp = new Node(tail, item, head);
                temp = this.head;
                while (temp.next.next != null)
                    temp = temp.next;
                Node lastNode = temp.next;
                temp.next = null;
                lastNode = null;
            }
        }
    }

    public void deletTarget(int n) {
        if (head == null) {
            return;
        } else {
            Node current = head;

            int pos = n;

            for (int i = 1; i < pos; i++) {
                current = current.next;
            }

            if (current == head) {
                head = current.next;
            } else if (current == tail) {
                tail = tail.previous;
            } else {
                current.previous = current.next;
                current.next.previous = current.previous;
            }
            current = null;
        }
    }
}