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I'm working on a Card game assignment and our lecturers want us to use different data structures. Now I have an ArrayList of Cards object and a HashMap of Points<Cards, Integer>. I'm trying to compare the HashMap key to the elements in the ArrayList to check the points for the Cards in the ArrayList but nothing seems to be working.

Here's the HashMap

    Map<Cards, Integer> Points = new HashMap<>();
    Points.put(new Cards("d", "A"), 1);
    Points.put(new Cards("c", "A"), 1);
    Points.put(new Cards("h", "A"), 1);
    Points.put(new Cards("s", "A"), 1);
    Points.put(new Cards("d", "2"), 2);
    Points.put(new Cards("c", "2"), 2);
    Points.put(new Cards("s", "2"), 2);
    Points.put(new Cards("h", "2"), 2);
    Points.put(new Cards("d", "3"), 3);
    Points.put(new Cards("c", "3"), 3);
    Points.put(new Cards("s", "3"), 3);
    Points.put(new Cards("h", "3"), 3);
    Points.put(new Cards("d", "4"), 4);
    Points.put(new Cards("c", "4"), 4);
    Points.put(new Cards("s", "4"), 4);
    Points.put(new Cards("h", "4"), 4);
    Points.put(new Cards("d", "5"), 5);
    Points.put(new Cards("c", "5"), 5);
    Points.put(new Cards("s", "5"), 5);
    Points.put(new Cards("h", "5"), 5);
    Points.put(new Cards("d", "6"), 6);
    Points.put(new Cards("c", "6"), 6);
    Points.put(new Cards("s", "6"), 6);
    Points.put(new Cards("h", "6"), 6);
    Points.put(new Cards("d", "7"), 7);
    Points.put(new Cards("c", "7"), 7);
    Points.put(new Cards("s", "7"), 7);
    Points.put(new Cards("h", "7"), 7);
    Points.put(new Cards("d", "8"), 8);
    Points.put(new Cards("c", "8"), 8);
    Points.put(new Cards("s", "8"), 8);
    Points.put(new Cards("h", "8"), 8);
    Points.put(new Cards("d", "9"), 9);
    Points.put(new Cards("c", "9"), 9);
    Points.put(new Cards("s", "9"), 9);
    Points.put(new Cards("h", "9"), 9);
    Points.put(new Cards("d", "X"), 10);
    Points.put(new Cards("c", "X"), 10);
    Points.put(new Cards("s", "X"), 10);
    Points.put(new Cards("h", "X"), 10);
    Points.put(new Cards("d", "J"), 10);
    Points.put(new Cards("c", "J"), 10);
    Points.put(new Cards("s", "J"), 10);
    Points.put(new Cards("h", "J"), 10);
    Points.put(new Cards("d", "Q"), 10);
    Points.put(new Cards("c", "Q"), 10);
    Points.put(new Cards("s", "Q"), 10);
    Points.put(new Cards("h", "Q"), 10);
    Points.put(new Cards("d", "K"), 10);
    Points.put(new Cards("c", "K"), 10);
    Points.put(new Cards("s", "K"), 10);
    Points.put(new Cards("h", "K"), 10);

Here's the ArrayList (Player1) of object Cards

    /**Cards class*/
    class Cards implements Comparable<Cards> {
    public String suit;
    public String face;
    
    public Cards() {
        
    }

    //Create Cards object 
    public Cards (String suit, String face){
        this.suit = suit;
        this.face = face;
    }

    //Return card suit
    public String getSuit() {
        return suit;
    }

    //Return card face
    public String getFace() {
        return face;
    }


    @Override
    public int compareTo(Cards currentCards) {
        if (getSuit().compareTo(currentCards.getSuit()) > 0) {
            return 1; 
        } else if ((getSuit().compareTo(currentCards.getSuit())) < 0){
            return -1; 
        } else if ((getSuit().compareTo(currentCards.getSuit())) == 0){
            if (getFace().compareTo(currentCards.getFace()) > 0){
                return 1;
            } else if (getFace().compareTo(currentCards.getFace()) < 0){
                return -1;
            }
        }
        return 0;
            
    }
    
    @Override
    public String toString() {
        return this.getSuit() + this.getFace();
    }
    }

/**Creating Cards object*/
String[] SUIT = new String[]{ "d", "c", "h", "s" };
String[] FACE = new String[]{ null, "A", "2", "3", "4", "5", "6", "7", "8", "9", "X", "J", "Q", "K" };
Cards[] cardDeck = new Cards[52];
int index = 0;
    
  for (int i = 0; i <= 3; i++) {
      for (int j = 1; j <= 13; j++) {
          cardDeck[index] = new Cards(SUIT[i], FACE[j]);
          index++;
      }
  }

/**Player 1 in hand*/
ArrayList<Cards> player1 = new ArrayList<Cards>();
int j=0;

    for (int i = 0; i <18; i++){
        player1.add(i, cardDeck[j++]);
    }

We tried this

for(Cards n : player1){
   if (Points.containsKey(n)){
       System.out.println("Card points: " + Points.get(n)); 
   }
}

The program compiles and run but the loop didn't go through as the print statement did not print

Mainaqisyah
  • 31
  • 4
  • Most likely, you didnt override the `equals()` and `hashCode()` methods in your Cards class. See https://stackoverflow.com/questions/1894377/understanding-the-workings-of-equals-and-hashcode-in-a-hashmap – GhostCat Mar 12 '21 at 09:03
  • Beyond that: normally you would using "raw" Strings for Suit and Face, but use an enum type. – GhostCat Mar 12 '21 at 09:04
  • And yes, your edit confirms it. Unless you **override** equals() (and ideally hashCode() accordingly), `new Card("d", "A").equals(new Card("d", "A")` returns FALSE. Because the default equals just compares object identity (aka "storage location"), not the data stored within your object. – GhostCat Mar 12 '21 at 09:06

0 Answers0