Biginner! Array to LinkedList

[SungsooKim]

Hello guys.

now I am studying about data structure. And I have some problems solving quizz

I have to change from array to linkedlist

But I am not sure which part I have to change.

Do I have to use nodes class? or just use linkedlist methods.

this is codes that I have to change

import java.text.NumberFormat;

public class CD
{
private String title, artist;
private double cost;
private int tracks;


public CD (String name, String singer, double price, int numTracks)
{
title = name;
artist = singer;
cost = price;
tracks = numTracks;
}

public String toString()
{
NumberFormat fmt = NumberFormat.getCurrencyInstance();

String description;

description = fmt.format(cost) + "\t" + tracks + "\t";
description += title + "\t" + artist;

return description;
}
}

//drive class

public class Tunes
{
//-----------------------------------------------------------------
// Creates a CDCollection object and adds some CDs to it. Prints
// reports on the status of the collection.
//-----------------------------------------------------------------
public static void main (String[] args)
{
CDCollection music = new CDCollection ();

music.addCD ("Storm Front", "Billy Joel", 14.95, 10);
music.addCD ("Come On Over", "Shania Twain", 14.95, 16);
music.addCD ("Soundtrack", "Les Miserables", 17.95, 33);
music.addCD ("Graceland", "Paul Simon", 13.90, 11);

System.out.println (music);

music.addCD ("Double Live", "Garth Brooks", 19.99, 26);
music.addCD ("Greatest Hits", "Jimmy Buffet", 15.95, 13);

System.out.println (music);
}
}

//I have to change this class...

import java.text.NumberFormat;

public class CDCollection
{
private CD[] collection;
private int count;
private double totalCost;

//-----------------------------------------------------------------
// Constructor: Creates an initially empty collection.
//-----------------------------------------------------------------
public CDCollection ()
{
collection = new CD[100];
count = 0;
totalCost = 0.0;
}

//-----------------------------------------------------------------
// Adds a CD to the collection, increasing the size of the
// collection if necessary.
//-----------------------------------------------------------------
public void addCD (String title, String artist, double cost,
int tracks)
{
if (count == collection.length)
increaseSize();

collection[count] = new CD (title, artist, cost, tracks);
totalCost += cost;
count++;
}

//-----------------------------------------------------------------
// Returns a report describing the CD collection.
//-----------------------------------------------------------------
public String toString()
{
NumberFormat fmt = NumberFormat.getCurrencyInstance();

String report = "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n ";
report += "My CD Collection\n\n";

report += "Number of CDs: " + count + "\n";
report += "Total cost: " + fmt.format(totalCost) + "\n";
report += "Average cost: " + fmt.format(totalCost/count);

report += "\n\nCD List:\n\n";

for (int cd = 0; cd < count; cd++)
report += collection[cd].toString() + "\n";

return report;
}

//-----------------------------------------------------------------
// Increases the capacity of the collection by creating a
// larger array and copying the existing collection into it.
//-----------------------------------------------------------------
private void increaseSize ()
{
CD[] temp = new CD[collection.length * 2];

for (int cd = 0; cd < collection.length; cd++)
temp[cd] = collection[cd];

collection = temp;
}
}

// I changed above class like this

import java.text.NumberFormat;
import java.util.*;


public class CDCollection
{
private CD[] collection;
private int count;
private double totalCost;
LinkedList<CD> list = new LinkedList<CD>();
//-----------------------------------------------------------------
// Constructor: Creates an initially empty collection.
//-----------------------------------------------------------------
public CDCollection ()
{
collection = new CD[100];
count = 0;
totalCost = 0.0;
}

public void addCD (String title, String artist, double cost,
int tracks)
{
for(int i = 0; i < collection.length; i++) {
collection[i] = new CD(title,artist,cost,tracks);
list.add(collection[i]);
count =i;
}

}


public String toString()
{
NumberFormat fmt = NumberFormat.getCurrencyInstance();

String report = "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n ";
report += "My CD Collection\n\n";

report += "Number of CDs: " + count + "\n";
report += "Total cost: " + fmt.format(totalCost) + "\n";
report += "Average cost: " + fmt.format(totalCost/count);

report += "\n\nCD List:\n\n";

for (int cd = 0; cd < count; cd++)
report += collection[cd].toString() + "\n";

return report;
}

//-----------------------------------------------------------------
// Increases the capacity of the collection by creating a
// larger array and copying the existing collection into it.
//-----------------------------------------------------------------
private void increaseSize ()
{
CD[] temp = new CD[collection.length * 2];

for (int cd = 0; cd < collection.length; cd++)
temp[cd] = collection[cd];

collection = temp;
}
}

the result is horrible...= (

Do you have any idea about this?

Thank you

[r035198x]

Please use code tags if you have to post code.
Are you supposed to write your own LinkedList class or are you allowed to use java.util.LinkedList?

[SungsooKim]

I don't care....better way is better..=)

[r035198x]

So what is this horrible result? Clean up your code first though. If you have a List<CD> you no longer need a CD[]. Get rid of that from your CDCollection class. Your add method should also change to simply add to the list.