difference method java using enum types

Question

I wish to write a method that can return the difference in value of 2 cards. Im confused as I\'m learning enums and not sure of the most efficient way to implement it.

Answer 1

public enum Rank {ACE(1), TWO(2); /* obviously add the other values*/
    private int value  ;
    Rank(int value){
        this.value = value;
    };
    public int getValue(){
       return this.value;
    }

    public int calcDifference(Rank rank){
        return getValue() - rank.getValue();
    }

};

which can then be called like so :

Rank rankAce =  Rank.ACE;
System.out.println(rankAce.calcDifference(Rank.TWO));

You could remove the int value and just use ordinal, but this way gives you a bit of flexibility.

Answer 2

The simplest way to define a value of a card is to add thirteen times the suit to the rank, or to add four times the rank to the suit:

public int faceValue(Card c) {
    return 13*c.getSuit().ordinal()+c.getRank().ordinal();
}

or

public int faceValue(Card c) {
    return 4*c.getRank().ordinal()+c.getSuit().ordinal();
}

Both ways produce numbers from 0 to 51, inclusive.

With faceValue in hand, you can define the difference function as follows:

public static int faceValueDifference(Card left, Card right){
    return left.faceValue()-right.faceValue();
}