Problem: Make a Card Orderable

A Card has a rank and a suit. The rank is a number from 2 to 14, where 11 through 14 stand for J, Q, K, and A. The suit is one of the characters 'C', 'D', 'H', 'S', standing for Clubs, Diamonds, Hearts, and Spades. Here is the starting point. The Card class has the two fields, a constructor, and getters:

public class Card {
  private int rank;
  private char suit;

  public Card(int rank, char suit) {
    this.rank = rank;
    this.suit = suit;
  }

  public int getRank() {
    return rank;
  }

  public char getSuit() {
    return suit;
  }
}

As the class stands, there is no way proper way to check if two cards are the same, and no way to sort a hand of cards. We want to add three things:

Value equality — two cards are the same card when their rank and suit match (equals and hashCode).
A natural order — cards are ordered by rank, then by suit (Comparable).
A second order — a Comparator that orders by suit, then by rank within a suit, without changing Card.

A working solution is provided in the accompanying code for this practice problem, in the practice package (Card.java, SuitComparator.java). Run scripts/run.sh practice.CardDemo to see it compare cards in two different orders.

Problem: Make a Card Orderable

Steps