Thread: Adding element to Linked List

I'm trying to understand the behavior of on how the elements of a String[] contentsOfBag are added into a linkedbag which is csc220bag (for this programming case).

First concern: from my understanding, each elements of String[] contentsOfBag are added such as element "A" goes into a Node with the data "A". Inside this same Node we have another Node where the next element "_" will be the data of this next Node and so on? Please correct me if I'm wrong/not totally correct.

Second concern is the purpose of constructor "private Node(T dataPortion)" & " private Node(T dataPortion, Node nextNode)" ?

It'll be very helpful for my understanding since I need to implement removeAllOccurences method. Ty

Here is the code :

Driver Code

public class LinkedBagCSC220JavaDriver {
 
    public static void main(String[] args) {
        System.out.println("=== LINKED BAG 220 JAVA ==========================================================");
        System.out.println("[+] Creating a CSC220 LinkedBag...");
        PrimaryDataStructureBagInterface<String> csc220Bag = new LinkedBag<>();
        testAdd(csc220Bag);
        testRemoveAllOccurrences(csc220Bag);
        System.out.println("=== LINKED BAG 220 JAVA ==========================================================");
    }
 
    private static void displayBag(PrimaryDataStructureBagInterface<String> aBag) {
        System.out.print("[>] The bag now contains " + aBag.getCurrentSize() + " string(s): \t");
        Object[] bagArray = aBag.toArray();
        for (Object bagArray1 : bagArray) {
            System.out.print(bagArray1 + " ");
        }
        System.out.println();
    }
 
    private static void testRemoveAllOccurrences(PrimaryDataStructureBagInterface<String> aBag) {
        // Removing all occurrences of the given entries from a bag
        System.out.println("[+] Creating... a 2D test array with the below contents: \t");
        String[][] testArray = {
                { "A", "A", "A", "A", "A", "A" },
                { "B", "A", "Bb", "B", "Bb", "B" },
                { "C", "B", "_", "A" },
                { "n", "u", "l", "l" }
        };
 
        for (String[] row : testArray) {
            System.out.print("\t\t\t\t\t");
            for (String col : row) {
                System.out.print(col + " ");
            }
            System.out.println("");
        }
 
        aBag.removeAllOccurrences(testArray);
        displayBag(aBag);
    }
 
    private static void testAdd(PrimaryDataStructureBagInterface<String> aBag) {
        // Adding strings
        String[] contentsOfBag = {
                "A", "_", "_", "G", "Bb", "A", "_", "u", "n",
                "o", "A", "o", "d", "Bb", "A", "A", "l", "l"
        };
        System.out.print("[+] Adding.... these items to the bag: \t");
        for (String entry : contentsOfBag) {
            aBag.add(entry); // trying to understand behind the scene of this line
            System.out.print(entry + " ");
        }
        System.out.println();
 
        displayBag(aBag);
    }
}

Linkedbag

public final class LinkedBag<T> implements PrimaryDataStructureBagInterface<T> {
 
    private Node firstNode;
    private int numberOfEntries;
 
    public LinkedBag() {
        firstNode = null;
        numberOfEntries = 0;
    }
 
    @Override
    public boolean removeAllOccurrences(T[][] entries) {
    }
 
    private class Node {
        private T data;
        private Node next;
 
        private Node(T dataPortion) {
            this(dataPortion, null);
        } // end constructor
 
        private Node(T dataPortion, Node nextNode) {
            data = dataPortion;
            next = nextNode;
        }
    }
}

Interface class - PrimaryDataStructureBagInterface

public interface PrimaryDataStructureBagInterface<T> {
 
    public int getCurrentSize();
 
    public boolean isEmpty();
 
    public boolean add(T newEntry);
 
    public boolean removeAllOccurrences(T[][] entries);
 
    public T[] toArray();
}

need the interface class

Yes, that class is needed to compile the code for execution testing.

Have you studied the structure of a linked list? Do a lookup on the internet and read up on what goes into a linked list.

After you have looked at the online documentation/description for linked lists, do you have any questions about your assignment?

Yes, that sounds like what a linked list is.
Did you lookup what a linked list is on the internet? Did you see anything different from what you thought?

Okay, I see. Also. quick question, were you able to compile the code. Cause as. it is when I try it says :

LinkedBagCSC220JavaDriver.java:32: error: cannot find symbol
    private static void displayBag(PrimaryDataStructureBagInterface<String> aBag) {
                                   ^
  symbol:   class PrimaryDataStructureBagInterface
  location: class LinkedBagCSC220JavaDriver
LinkedBagCSC220JavaDriver.java:41: error: cannot find symbol
    private static void testRemoveAllOccurrences(PrimaryDataStructureBagInterface<String> aBag) {
                                                 ^
  symbol:   class PrimaryDataStructureBagInterface
  location: class LinkedBagCSC220JavaDriver
LinkedBagCSC220JavaDriver.java:63: error: cannot find symbol
    private static void testAdd(PrimaryDataStructureBagInterface<String> aBag) {
                                ^
  symbol:   class PrimaryDataStructureBagInterface
  location: class LinkedBagCSC220JavaDriver
LinkedBagCSC220JavaDriver.java:26: error: cannot find symbol
        PrimaryDataStructureBagInterface<String> csc220Bag = new LinkedBag<>();
        ^
  symbol:   class PrimaryDataStructureBagInterface
  location: class LinkedBagCSC220JavaDriver
LinkedBagCSC220JavaDriver.java:26: error: cannot find symbol
        PrimaryDataStructureBagInterface<String> csc220Bag = new LinkedBag<>();
                                                                 ^
  symbol:   class LinkedBag
  location: class LinkedBagCSC220JavaDriver

How am I suppose to make it run? I don't understand the error..

LinkedBagCSC220JavaDriver.java:32: error: cannot find symbol

Where is the PrimaryDataStructureBagInterface.class file that defines PrimaryDataStructureBagInterface?
The compiler can not find it.

Since none of your classes are in packages, if all the source files are in the same folder then the compiler will be able to find them.

Good, I am glad you have it working now.