Question

The JCF provides numerous classes that implement the List interface, including LinkedList, ArrayList, and Vector. Write code to show how the JCF class ArrayList and LinkedList are used to maintain a grocery list. Verify List methods such as "add()", get(), "remove()", "isEmpty()" and "size()" by implementing a test program.

import java.util.ArrayList;
import java.util.Iterator;

public class GroceryList {
static public void main(String[] args){
ArrayList<String> groceryList = new ArrayList<String>();
Iterator<String> iter;
  
groceryList.add("apples");
groceryList.add("bread");
groceryList.add("juice");
groceryList.add("carrots");
groceryList.add("ice cream");
  
System.out.println("Number of items on grocery list:" + groceryList.size());
System.out.println("Items are: ");
iter = groceryList.listIterator();
while(iter.hasNext()) {
String nextItem = iter.next();
System.out.println(groceryList.indexOf(nextItem)+ " " + nextItem);
}// end while
  
}//end main
} //end GroceryList
  

Answer 1

Answer: Hello! here are two programs one is for ArrayList and the other is LinkedList. I used in ArrayList program list methods to maintain a grocery list and method of linked list used in another program. Comments are given in each program. thanks.

import java.util.ArrayList;
import java.util.Iterator;

public class GroceryList //import packages
{
static public void main(String[] args) //main function
{
   int size; //int variable to store size
   String item; //string type varisble to store an item
ArrayList<String> groceryList = new ArrayList<String>(); //create list
Iterator<String> iter;
boolean ans=groceryList.isEmpty(); //boolean type variable to check list
  
if(ans==true) //checking variable
System.out.println("List is Empty");
else
   System.out.println("List is not Empty");

//add items to list

       groceryList.add("apples");
       groceryList.add("bread");
       groceryList.add("juice");
       groceryList.add("carrots");
       groceryList.add("ice cream");
       System.out.println(" ");
          

//printing items of a list

           System.out.println("Number of items on grocery list:" + groceryList.size());
           System.out.println("Items are: ");
           iter = groceryList.listIterator();
           while(iter.hasNext()) {
           String nextItem = iter.next();
           System.out.println(groceryList.indexOf(nextItem)+ " " + nextItem);
           }// end while
//again checking list is empty or not
           System.out.println(" ");
           ans=groceryList.isEmpty();
       if(ans==true) //checking variable
           System.out.println("List is Empty");
       else
           System.out.println("List is not Empty");
       System.out.println(" ");
          
           groceryList.remove("juice"); //remove item "juice"
           System.out.println("Removed Juice Item from list");
           System.out.println(" ");
//after removing display list
           System.out.println("After remove item Modified grocery list:" + groceryList.size());
           iter = groceryList.listIterator();
           while(iter.hasNext()) {
           String nextItem = iter.next();
           System.out.println(groceryList.indexOf(nextItem)+ " " + nextItem);
           }// end while
//size method used to get size of list
           size=groceryList.size(); //size method
           System.out.println("Size of List: "+size);
           System.out.println(" ");
          
           item=groceryList.get(2); //get method use to get item from a list
           System.out.println("we got item of index two: "+item);
          
      
}//end main
} //end GroceryList

import java.util.*;
public class Test //class test
{
public static void main(String args[]) //main function
{
// Creating object of class linked list
LinkedList<String> item = new LinkedList<String>();
  
// Adding items to the linked list
item.add("Apples");
item.add("Bread");
item.addLast("Chocolate");
item.addFirst("Biscuit");
item.add(2, "Juice");
item.add("Shake");
item.add("ButterMilk");
System.out.println("Linked list : " + item);
  
// Removing items from the linked list
item.remove("Bread");
item.remove(3);
item.removeFirst();
item.removeLast();
System.out.println("Linked list after deletion: " + item);
  
// Finding items in the linked list
boolean status = item.contains("Shake");
  
if(status)
System.out.println("List contains the item 'Shake' ");
else
System.out.println("List doesn't contain the item 'Shake'");
  
// Number of items in the linked list (size)
int size = item.size();
System.out.println("Size of linked list = " + size);
  
// Get and set items from linked list
String element = item.get(2);
System.out.println("Item returned by get() : " + element);
item.set(2, "ProteinShake");
System.out.println("Linked list after change : " + item);
}
}