array list help

[dorno83]

I'm having problem learning some simple java programming. I bought a book and this is one of the questions in the book. I was wondering if anyone could help me work through this.

"Implement a class Purse. A purse contains a collection of coins. For simplicity, we will only store the coin names in an ArrayList<String>.
Supply a method

void addCoin(String coinName)

Add a method toString to the Purse class that returns a string showing the coins in the purse in the format

Purse[Quarter, Dime, Nickel, Dime]


Thanks

[CJSLMAN]

Maybe this will help:

List Implementations (The Java™ Tutorials > Collections > Implementations)

[Norm]

Take it one step at a time.
Write the basic structure for a class.
Add the two methods. Leave them empty for now, except for a System.out.println() to show it was called.
Add a main to create an instance of the class and to call its two methods.
Compile and test the program.
Come back if any problems.
Then we'll work on adding code to each of the methods.

[Eranga]

Yes take a single step at a time. Can you show what you have done so far here.

[dorno83]

OK so I went a little further and it semi works. I'm just not using my array list yet.

import java.util.ArrayList;
import java.util.Scanner;
/**
* Write a description of class PokerHand here.
*
* @author Matthew Doran
* @version 06 NOV 08
*/
public class PurseCoins
{
// instance variables - replace the example below with your own
private String coin;

/**
* Constructor for objects of class PurseCoins.
*/
public PurseCoins(String coinAdded)
{
coinAdded = coin;
}

public void addCoin(String coinName)
{
ArrayList<String> coin = new ArrayList<String>();
coin.add("Quarter");
coin.add("Dime");
coin.add("Nickel");
coin.add("Penny");

}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
System.out.print ("Enter coin to add: ");
String coinAdded = in.nextLine();
String addCoin = new String();

if (coinAdded.equalsIgnoreCase(coinAdded))
{
addCoin = coinAdded;
}



System.out.println("Purse[ " + addCoin);

// System.out.println(coin.get(0)
// + coin.get(1)
// + coin.get(2));
}
}

[Eranga]

Ok, is this code working? Do you have any questions on this?

Please use code tags when you posting again.

[dorno83]

The code works but its not right.
Its supposed to show all the coins added to the purse not just one.

[Eranga]

You mean this.

System.out.println(coin.get(0)

So, loop through the list from first to last element.

[dorno83]

how do I do that?

[Eranga]

Do something like this,

        for(int i = 0; i < coin.size(); i++) {
            System.out.println(coin.get(i));
        }

But actually you cannot do that in main method, because VM cannot see that your list. Basically it scope is not valid in main method. You should define it in global level.