Problem comparing two ArrayLists, elements must match, order not important.

Question

Hello,
I am new to Java and my assignment is:
Write a method for the Purse class - public boolean sameCoins(Purse other), that checks whether the other purse has the same coins, perhaps in a different order.
For example, the purses:
*Purse[Quarter,Dime,Nickel,Dime]*
and
*Purse [Nickel,Dime,Dime,Quarter]*
should be considered equal.
You will probably need one or more helper methods.
I was able to make a method to check if the purses match(sameContents), but I have not been able to check if they match just based on elements(sameCoins). We are not using Collections.
Below is my Purse Class:
import java.util.ArrayList;
public class Purse {
    private ArrayList<String> coins;
    public Purse() {
        coins = new ArrayList<String>();
    public void addCoin(String coinName) {
        coins.add(coinName);
    public String toString() {
        String text = "Purse[ ";
        for (String a : coins)
            text += a;
        text += "]";
        return text;
    public boolean sameContents(Purse other) {
        boolean content = false;
        if (other.coins.equals(coins))
            content = true;
        return content;
    public boolean sameCoins(Purse other){
        boolean samecoins = true;
        for(String a: coins)
            for(String b: other.coins)
                if (a.contains(b))
                    samecoins = true;
                else
                    samecoins=false;
        return samecoins;
}Any help would be appreciated.

Answer 1

tipalm wrote:
Well then my prof cant hold it against me can he!He sure can, if he wants to. I'll bet you 30 duke stars that if you hand in the program as-is and try to argue for using the Collections framework, he's going to say "I meant you couldn't use any of the static methods in the Collections framework, the whole point of the assignment was to work through the logic of iterating through the Lists" But hey, it's not my assignment, so good luck!
Edit- I'm not saying that using the Collections framework (and its myriad static methods) is bad in any way. It's actually what you should use, assuming there are no academic "but don't use this shortcut" rules being applied. I just doubt that's your case here. I'd recommend looking into how the Collections framework works, and then implement your own algorithm based on that.
Edited by: kevinaworkman on Oct 29, 2009 10:13 AM