Question

LinkedListBox

Patterned after the ArrayBox assignment, please create your own implementation of LinkedList called LinkedListBox as explained in class. Refer to the class slides on linked lists. Specifically, implement your generic classes as:

public class LinkedListNode
{
public E element;
public LinkedListNode next;
}
public class LinkedListBox
{
public LinkedListNode head;
public LinkedListNode tail;
public int count = 0;
}

Within the LinkedListBox class, implement the following methods:

public boolean add(E e). Returns true after adding an element to the end of the list.

public E get(int idx). Returns element at index position idx.

public E set(int idx, E e). Changes the element at position idx to e. Returns old element.

public E remove(int idx). Removes element at position idx from the list and returns it.

public int size(). Self-explanatory

public boolean isEmpty(). Self-explanatory

public Integer find(E e). Search for element e in the linked list and return its index position or return null if not found.

public E removeFirst(). Remove and return the element at the head of the list.

public E removeLast(). Remove and return the element at the tail of the list.

public void addFirst(E e). Add an element to the front of the list.

public void insert(int idx, E e). Insert an element right after the index idx position.

Create a driver class called LinkedListBoxDriver. Provide the user a menu:

=[==[==[=[=================================]=]==]==]=
=[==[==[=[ Welcome to LinkBox ]=]==]==]=
=[==[==[=[=================================]=]==]==]=

Choose...

1. Add an element(String) to our box.
2. Remove an element(String) from our box.
3. Replace(set) an element(String) from our box.
4. Insert an element(String) after index.
5. List the contents of the box.
6. Exit program

please don't answer the same solution what already exist in chegg. Thanks

Answer 1

import java.util.*;
class LinkedListNode<E>{
   public E element;
   public LinkedListNode<E> next;
   LinkedListNode(E e)
{
element = e;
next = null;
}
LinkedListNode(E data, LinkedListNode<E> next) {
this.element = data;
this.next = next;
}
}

class LinkedListBox<E>{
   public LinkedListNode<E> head;
   public LinkedListNode<E> tail;
   public int count=0;

   public boolean add(E e){
       LinkedListNode<E> node = new LinkedListNode<E>(e);
       node.next=null;
       if(head==null)
           head=node;
       else{
           tail = head;
           while(tail.next != null)
               tail = tail.next;
           tail.next=node;
       }
       count++;
       return true;
   }

   public E get(int idx){
       int i=0;
       LinkedListNode<E> node = head;      
       while(node.next!=null){
           if(i==idx){
               return node.element;
           }
           i++;
           node = node.next;
       }
       return node.element;
   }

   private LinkedListNode<E> goTo(int index) {
LinkedListNode<E> current = head;
for (int i = 0; i < index; i++) {
current = current.next;
}
return current;
    }

   public E set(int index, E value) {
       LinkedListNode<E> current = goTo(index);
       E e = current.element;
       current.element = value;
       return e;
    }

   public E remove(int idx){
       E ele = head.element;
       if (idx == 0) {
           head = head.next;
       } else {
           LinkedListNode<E> current = head;
           for(int i = 0; i < idx - 1; i++) {
               current = current.next;
           }
           ele = current.next.element;
           current.next = current.next.next;
       }
       count--;
       return ele;
   }

   public int size(){
       return count;
   }

   public boolean isEmpty(){
       if(head==null)
           return true;
       return false;
   }

   public int find(E e){
       LinkedListNode<E> node = head;
       int i=0;
       while(node.next != null){
           if(node.element==e){
               return i;
           }
           i++;
           node = node.next;
       }
       return -1;
   }

   public E removeFirst(){
       E ele = head.element;
       head = head.next;
       count--;
       return ele;
   }

   public E removeLast(){
       E ele = head.element;
       tail=head;
       while(tail.next.next!=null)
           tail = tail.next;
       ele=tail.element;
       tail.next=null;
       count--;
       return ele;
   }

   public void addFirst(E e){
       LinkedListNode<E> node=null;
       node.element=e;
       node.next=head;
       head=node;
       count++;
   }

   public void insert(int index, E value){
       if (index == 0) {
head = new LinkedListNode<E>(value,head);
} else {
LinkedListNode<E> current = head;
for(int i = 0; i < index - 1; i++) {
current = current.next;
}
current.next = new LinkedListNode<E>(value, current.next);
}
       count++;
   }

   public void print(){
       LinkedListNode<E> current = head;
       while(current.next != null){
           System.out.print(current.element+"->");
           current=current.next;
       }
       System.out.println(current.element);
   }

}

class LinkedListBoxDriver{
   public static void main(String[] args) {
       LinkedListBox lst = new LinkedListBox();
       System.out.println("Welcome to LinkBox");
       String s;
       int idx;
       do{
           System.out.println("Choose");
           System.out.println("1. Add an element(String) to our box");
           System.out.println("2. Remove an element(String) from our box");
           System.out.println("3..Replace(set) an element(String) from our box");
           System.out.println("4. Insert an element(String) after index");
           System.out.println("5. List the contents of the box");
           System.out.println("6. Exit");
           int ch;
           Scanner sc = new Scanner(System.in);
           ch = sc.nextInt();
           switch(ch){
               case 1:
                   System.out.println("Enter String");
                   s = sc.next();
                   System.out.println(lst.add(s));
                   break;
               case 2:
                   System.out.println("Enter index");
                   idx = sc.nextInt();
                   System.out.println(lst.remove(idx));
                   break;
               case 3:              
                   System.out.println("Enter index");
                   idx = sc.nextInt();
                   System.out.println("Enter String");
                   s = sc.next();
                   System.out.println(lst.set(idx,s));
                   break;
               case 4:                  
                   System.out.println("Enter index");
                   idx = sc.nextInt();
                   System.out.println("Enter String");
                   s = sc.next();
                   lst.insert(idx,s);
                   break;
               case 5:
                   lst.print();
                   break;
               case 6:
                   System.exit(0);
               default: System.out.println("Invalid Input");
           }
       }while(true);
   }
}