/*
 * T05n03.java -- Demonstration of an implementation of the Comparable
 * interface.
 *
 * Comparable is perhaps the easiest of the standard Java interfaces
 * to implement, because it has only one method:  compareTo().
 *
 * In this example, we have a PlayingCard class that implements Comparable.
 * Here, compareTo() is required to accept an Object as its argument, so a
 * bit of type-casting is necesssary.  This is how you'd have to code a
 * method that implements an interface in a pre-1.5 version of Java.
 * To see how Java 1.5 simplifies this, see the next example program.
 *
 * Something else to note:  compareTo() returns an int instead
 * of returning a boolean.  This is because there are three possible
 * outcomes of a comparison: a<b, a==b, or a>b.  compareTo() follows the
 * tradition of the strcmp() function from the language C:  When a<b,
 * return a negative #; when a>b, return a positive number; when a==b,
 * return 0.  Here we just use -1 and +1, but sometimes the magnitude of
 * the value has meaning, too.
 */

import java.io.*;

class PlayingCard implements Comparable
{
    char suit;         // 'C', 'D', 'H', or 'S'
    int rank;          // 2, 3, ..., 9, 10, 11 (J), 12 (Q), 13 (K), 14 (A)

    PlayingCard ()
    {
        rank = (int)Math.floor(Math.random()*13) + 2;   // 0-12 + 2 = 2-14

        assert (rank>1)&&(rank<15);  // verify that the rank is in range

        switch ((int)Math.floor(Math.random()*4)) {
            case  0: suit = 'C';
            case  1: suit = 'D';
            case  2: suit = 'H';
            case  3: suit = 'S';
            default: suit = '#';
        }
    }

    PlayingCard (char fromSuit)
    {
        rank = (int)Math.floor(Math.random()*13) + 2;   // 0-12 + 2 = 2-14
        suit = fromSuit;
    }

    PlayingCard (int fromRank, char fromSuit)
    {
        suit = fromSuit;
        rank = fromRank;
    }

    public  int getRank() { return rank; }

    public char getSuit() { return suit; }

    public String toString()
    {
        String temp = "";
        if (rank < 11) temp += rank;
        else switch (rank) {
                 case 11: temp += "Jack"; break;
                 case 12: temp += "Queen"; break;
                 case 13: temp += "King"; break;
                 case 14: temp += "Ace";
             }
        temp += " of ";
        switch (suit) {
            case 'C': temp += "Clubs"; break;
            case 'D': temp += "Diamonds"; break;
            case 'H': temp += "Hearts"; break;
            case 'S': temp += "Spades";
        }
        return temp;
    }

    public int compareTo (Object cardObject)
    {
        PlayingCard card = (PlayingCard) cardObject;

        if ( (suit == card.getSuit()) && (rank == card.getRank()) ) return 0;
        if (rank < card.getRank()) return -1;
        if ( (rank == card.getRank()) && (suit < card.getSuit()) ) return -1;
        return 1;
    }

}


public class T05n03
{
    public static void compareThem(PlayingCard card1, PlayingCard card2)
    {
        if (card1.compareTo(card2) < 0) 
            System.out.println(card1 + " is less than " + card2);
        else if (card1.compareTo(card2) > 0) {
            System.out.println(card1 + " is greater than " + card2);
        } else {
            System.out.println(card1 + " is equal to " + card2);
        }
    }

    public static void main (String [] args) 
    {
        int limit,
            powerOf2;

        PlayingCard card1 = new PlayingCard(14,'D'),
                    card2 = new PlayingCard(6,'S'),
                    card3 = new PlayingCard(14,'S'),
                    card4 = new PlayingCard(13,'D'),
                    card5 = new PlayingCard(6,'S');

        compareThem(card1,card2);  // diff. objects, diff. suits, diff. ranks
        compareThem(card2,card1);  // diff. objects, diff. suits, diff. ranks
        compareThem(card1,card3);  // diff. objects, diff. suits, same  ranks
        compareThem(card4,card1);  // diff. objects, same  suits, diff. ranks
        compareThem(card2,card5);  // diff. objects, same  suits, same  ranks
        compareThem(card2,card2);  // same  object!
    }
}