Dummy Headed Doubly Circular Linked List (SOLVED)

Instructions for students:
1. Complete the following methods on Linked lists.
2. You may use any language to complete the tasks.
3. You need to submit one single file containing all the methods/functions.The form
will be open till 2 days after the due date. 30% marks will be deducted for each
late day in case of late submission.
4. The submission format MUST be maintained. You need to copy paste all your
codes in ONE SINGLE .txt file and upload that. If format is not maintained, whole
lab submission will be canceled.
5. If you are using JAVA, you must include the Tester class containing the main
method which should test your other methods in DoublyList class and print the
outputs according to the tasks.
6. If you are using PYTHON, make sure your code has the methods invoked
through test statements and proper printing statements according to the tasks.
You may create a separate Tester class for this or test the methods within the
DoublyList class.
7. Usage of built in methods/libraries are NOT ALLOWED
8. The google form link for this lab is provided in BUX under LAB 3 Doubly Linked
Lists subsection under the FALL21 CSE220 lab tab.
Dummy Headed Doubly Circular Linked List
Task 1:
i) Create a Node class which will hold three fields i.e an integer element and a
reference to the next Node along with a reference to the previous Node.
ii) Create a Dummy Headed Doubly Circular Linked list Abstract Data Type
(ADT)named DoublyList.The elements in the list are Nodes consisting of an integer
type key (all keys are unique) and a reference to the next node and a reference to the
previous Node.
[You are not allowed to use any global variable other than head.]
Task 2: (Basic operations) (20 marks)
1. Constructors: (3)
a. DoublyList (int [] a) or def __intit__(self,a)
Pre-condition: Array cannot be empty.
Post-condition:This is the default constructor of MyList class. This
constructor creates a Dummy Headed Doubly Circular Linked list list
from an array.
2. void showList ( ) or def showList(self) (1)
Precondition: None.
Postcondition: Outputs the keys of the elements of the order list. If the list is
empty, outputs “Empty list”.
3. void insert (Node newElement ) or def insert(self, newElement) (4)
Pre-condition: None.
Post-condition: This method inserts newElement at the tail of the list. If an
element with the same key as newElement already exists in the list, then it
concludes the key already exists and does not insert the key.
4. void insert (int newElement, int index) or def insert(self, newElement, index) (4)
Pre-condition: The list is not empty.
Post-condition: This method inserts newElement at the given index of the list. If
an element with the same key as newElement value already exists in the list,
then it concludes the key already exists and does not insert the key. [You must
also check the validity of the index].
5. void remove (int index) or def remove(self, index) (4)
Pre-condition: The list is not empty.
Post-condition: This method removes the Node at the given index of the list.[You
must also check the validity of the index].
6. int removeKey(int deleteKey) or def removeKey(self, deletekey) (4)
Pre-condition: List is not empty.
Post-condition: Removes the element from a list that contains the deleteKey and
returns the deleted key value.