Thread: Creating a series of objects with incrementing names

Let me see if I can explain this right. I have this program (same as from my last thread) to create 52 objects that represent playing cards. I am using a for() loop to run over the object creation 52 times, thus creating 52 cards, but I don't want to have to name each one (indeed, that wouldn't even work in a for() loop).

How can I increment the card's names? For instance, first object is Card1, then Card2, Card3, Card4 and so forth?

Also, a little secondary question:

class Card {
 
  private static String[][] type = {
      {"clubs", "diamonds", "hearts", "spades"},
          {"ace", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "jack",
          "queen", "king"}
  };
 
  private String suit, rank;
  private static final int suitCall1 = 0;
  private static int suitCall2 = 0;
  private static final int rankCall1 = 1;
  private static int rankCall2 = 0;
 
        public Card() {
            if(rankCall2 == 12) {
                suitCall2++;
            }
            suit = type[suitCall1][suitCall2];
            rank = type[rankCall1][rankCall2++];
 
}
 
}

As you can see, there wouldn't actually be a problem only running this code 52 times, but if it ran a 53rd time, there would (I assume) be a compiler error because suitCall2 could not be incremented again due to going out of range of the array. I'm going to guess this is where exception handling comes in? If so, don't bother answering because that comes up in a later lesson and I don't want to confuse myself lol.

Thanks,
-s45

You have some ideas jumbled up, and your question isn't clear. I'm not really sure what you're asking when you wander off into 53 versus 52 cards.

The 52 Card objects represent a deck, and the creation of a Deck does not belong in the Card class. Cards should know nothing about Decks. The Deck class (or however the deck is created) decides how many Card objects there are in a Deck object, creates the card objects with that number of distinct characteristics, like 4 suits of 13 ranks. Following that design, a card should include the fields 'suit' and 'rank' and not have a 'name'. Frankly, if you renamed what you posted Deck and modified it slightly as shown below, you'd be closer. (Why did you have an 'ace' and a '1'?)

// class Deck creates a standard deck of 52 cards of 4 suits of 13 ranks each
class Deck
{
	private static String[] suit = {"clubs", "diamonds", "hearts", "spades"};
	private static String[] rank = {"ace", "2", "3", "4", "5", "6", "7",
		"8", "9", "10", "jack", "queen", "king"};
 
	Card[] cards;
 
	// default constructor
	public Deck()
	{
		cards = new Card[suit.length * rank.length];
 
		for ( int i = 0 ; i < suit.length ; i++ )
		{
			for ( int j = 0 ; j < rank.length ; j++ )
			{
				cards[suit.length * i + j] = new Card( suit[i], rank[j] );
			}
		}
 
	} // end default constructor Deck()
 
	// other Deck methods as needed . . .
 
} // end class Deck

Wow... that's a good approach, lol. Here's the thing: The code you posted isn't hard to understand, but I wonder if you have advice for me on how one should THINK as a programmer to have stuff like that come so easily? I mean especially this nested for() loop and the cards[suit.length * i + j] algorithm - if you follow the code, that works out exactly so that cards[] will step up each time. But how did you think to do that? I'm not sure how to frame this question right, and maybe I'm just not mathematically minded enough, but - it looks to me like you knew automatically that multiplying the number of suits by the current suit and adding the current rank would increment cards[] correctly in the code. But for me, if I had ever thought to write that, it would have only gotten that way because I had figured out that that operation would produce the right number result, rather than just knowing it off hand. Do you get what I'm asking?

Maybe it's a stupid or even weird question - I just want to understand how to think to be able to have these solutions come so easily. Not just the cards[] algorithm but even the nested for() loops. I'm not sure how long it would have taken me to think of doing either.

-s45

EDIT: Well, after thinking a bit more about cards[suit.length * i + j] I understand the math concept now, but I still think I need to learn how to think like a programmer better.

Originally Posted by summit45

how one should THINK as a programmer to have stuff like that come so easily?

Practice problem solving often.

Originally Posted by summit45

mathematically minded

Math is a big part of it.

Originally Posted by summit45

multiplying the number of suits by the current suit and adding the current rank would increment cards[] correctly

The same math will be used frequently acting on arrays. More practice will reveal this as a common pattern

I find math easy, always have, so I can't pretend to see the problem from a perspective that finds math challenging, foreign, or scary. Even so, I wasn't born knowing these common programming patterns, so I learned them just like you will. Ask questions, read other people's code, and then practice, practice, practice, . . ., practice applying what you find interesting and want to learn until it just flows. It can happen, but it comes from your curiosity, desire to learn, and then nearly endless practice as is required to master any skill, unless you're a prodigy or savant.

Yaay, my code words now. It all came to me last night/this morning. It's amazing how programming does that. I just don't get it, then later, I do, lol. But anyway here it is. By the way Greg, I appreciate your suggestion about a Deck class. That will actually help me a lot with the next exercise in the lesson, but this one was just about creating a Card class. Creating a "deck" and writing it to std/out was just my idea to test the code.

package cardsexercise;
 
class Card {
 
  private static String[] suits = {"Clubs", "Diamonds", "Hearts", "Spades"};
 
 
private static String[] ranks = {"Ace", "2", "3", "4", "5", "6", "7", "8", "9", "10", "Jack",
          "Queen", "King"};
 
//Following two int vars will monitor position in the array and increment
//the card being created.
  private static int suitCall = 0;
  private static int rankCall = 0;
  private String suit, rank;
 
  public Card() { //First check if the suit needs to be advanced.
      if(rankCall == ranks.length) {
          rankCall = 0;
          suitCall++;
      }
      suit = suits[suitCall];
      rank = ranks[rankCall++];
 
}
 
  public static int getTotalCards() {
      return suits.length * ranks.length;
}
 
  public String getSuit() {
      return suit;
  }
public String getRank() {
    return rank;
}
}
 
public class CardsExercise {
 
 
    public static void main(String[] args) {
 
    int numCards = Card.getTotalCards();
    Card[] cards;
    cards = new Card[numCards]; //Create a Card array of a length equal
                                //to the total possible number of cards.
 
        for(int i = 0; i < numCards; i++) { //Fill the card array.
 
            cards[i] = new Card();
        }
 
        for(int i = 0; i < cards.length; i++) {
            int h = i; //Buffer var to shield i from the incrementation by j.
            int j = ++h;
            String k = cards[i].getSuit();
            String n = cards[i].getRank();
            System.out.println("Card " + j + ": " + n + " of " + k);
 
        }
 
}
}

-s45