/**
 * A bank card.  Each card is associated with an account.
 * Given a card, it is not possible to determine the account number.
 * It is possible to compare two cards and determine if they are for the same account.
 * 
 * This is an implementation of a bank card as described in Kleinberg & Tardos, Chapter 5, Problem 3.
 * @author Barbara Lerner
 *
 */
public class BankCard {
	/** The account that the card is for.  There is intentionally no getter or setter
	 *  for this field.  (Pretend it is encrypted.)
	 */
	private int account;
	
	/**
	 * Create a card for an account
	 * @param acct the account the card is for
	 */
	public BankCard(int acct) {
		account = acct;
	}
	
	/**
	 * Compare two cards. 
	 * @param o the other card
	 * @return true if the other card and this card are for the same account.
	 */
	public boolean equals (Object o) {
		if (o == null) {
			return false;
		}
		
		if (!(o instanceof BankCard)) {
			return false;
		}
		
		BankCard other = (BankCard) o;
		return other.account == account;
	}
}