Implementation of the List ADT by use of a backing Linked List

Program name: FriendLink.java

implement the behaviors of the List Abstract Data Type $($ADT$)$ by using a java Linked List as storage.

$$These $5$ behaviors are: size$(),$ get$(),$ set$(),$ add$(),$ remove$().$ We will use a singly linked list which stores the names of my friends $$ in the order I want $$ in its nodes.

We implement all the List ADT commands.

ADD index name

Implements the add$()$ list behavior

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REMOVE index

Implements the remove$()$ list behavior

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SET index name

Implements the set$()$ list behavior

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GET index

Implements the get$()$ list behavior

$$

PRINT

Prints out the current list and current size of the list

size$()$ implemented

$$Extra command $-$ which is not for List $$ but needs to implement

CONTAINS name

Determines if nameis in the list $$ if so$,$ prints out the index position of the first occurrence of name.$$ If not, it simply reports that name is not in the list.

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Generally, each command and its arguments are typed at the CLI all in one line $$ with one blank space separating the entities.$$ So$,$ the input lines are blank$-$space$-$separated Strings.

More on this program $....$

I have only a few friends $$ but occasionally, I will add a new one $$ or even lose one!$$ I will create a java linked list to keep track of the first names of my friends.$$ I want the Linked List to list the friends I have now, but also to grow in case I add any new friends.$$ There is also the possibility of losing a friend sometimes!

So$,$ I want a linked list that names all my friends $$ in the order I want them in $$ and I want to implement the ADT List operations in the table above for my list.$$Unlike the array case, we make no assumptions about how many friends I might have $$ as the linked list can grow as needed.

start the program with an initial list of friends $$ But the first job of your program is to put these names $$ in proper linked order $$ into the nodes of a linked list.

String $[]$ friend $=\{$Annie$,$Elbert$,$Andrew$,$Harry$,$Charles$,$Mary$,$Frank$,$Sandy$,$Elvis$\}$;$//$ line $$

program will use a Scanner to repeatedly input a one$-$line request presenting any of the commands in the table above $-$ and then$$ responds to that command $$ then goes back and reads in another command until an EOF condition is hit.$$ With commands being typed in at the CLI, an EOF condition is created by control$-$z followed by enter key.$$ The main loop of your program uses a while statement of the form:

while$($sc$.$hasNextLine$())\{....\}//$ where sc points to your Scanner

Before starting the loop to input commands $$ the program should print out the initial list and the initial size of the list $($which is $9).$

Your program should define Node and Linked List as in the picture below:

You program starts by creating an empty Linked List object ls as below:

LinkedList ls $=$ new LinkedList$()$;

This is ultimately to contain nodes for all the names of my friends. This first job of the program is to populate the linked list one node at a time $$ creating a node for each name in the friend$[]$ array $($shown above$)$ and linking each to the appropriate next name via its next field.$$ So$,$ you go through the friend$[]$ array element by element, and for each element create a new Node for the friend$[$i$]$ as i runs from $0$ to friend.length$-1.$

So you create:

$$ new Node$($friend$[$i$])$

and you make sure the previous node you had links to this.

If the initial list has "Annie" first $$ then the node you make for "Annie" should be the head of the list $$ so

ls$.$head $=$ new Node$($friend$[0])$;$($line $\backslash$alpha $)$

and ultimately $$ when you get to "Elvis" in the list $$ the node you make for that will be the tail of the list.

To build the initial linked list ls $$ as you sequence through it $-$ you will need a general node pointer $$ current $$ to point to the node you are currently on$.$ Assuming you used line $\backslash$alpha above $$ you could say

Once the program has built the linked list as above $$ as part of initialization $$ you want to print out the names of all the friends in order $$ by linking through the linked list.$$ Here you can count them as you go along and remember $$ in a variable size $$ how many friends I have.$$ Now you are ready to go into the command reception loop.

Your command reception while loop $$ and your switch$/$case statement for the various commands $$ these should be exactly based on a static array.