import java.text.DecimalFormat;

/****
 *
 * This is a version of the BankAccount class that implements the Comparable
 * interface.  It has exactly two differences with the original definition of
 * BankAccount:
 *
 *   (1) implementation of Comparable<BankAccount>
 *   (2) addition of the compareTo method
 *
 * See lecture notes Week 4 for some discussion.
 *
 */
public class BankAccount implements Comparable<BankAccount> {

    /** The current balance of this bank account. */
    private double balance;

    /** Name of the banking institution for this account. */
    private String institution;

    /**
     *  Construct a bank account with a zero balance.
     */
    public BankAccount() {   
        balance = 0;
    }

    /**
     * Construct a bank account at the given institution, with the given
     * initial balance.
     */
    public BankAccount(String institution, double balance) {
        this.balance = balance;
        this.institution = institution;
    }

    /**
     * Deposit the given amount of money into this bank account.
     */
    public void deposit(double amount) {  
        if (amount < 0) {
            throw new IllegalArgumentException();
        }
        balance = balance + amount;
    }

    /**
     * Withdraw the given amount of money from this bank account.
     */
    public void withdraw(double amount) {   
        if ((balance - amount < 0) || (amount < 0)) {
            throw new IllegalArgumentException();
        }
        balance = balance - amount;
    }

    /**
     * Get the current balance of this bank account.
     */
    public double getBalance() {   
        return balance;
    }

    /**
     * Transfer the given amount from this account to the given other account.
     */
    public void transfer(double amount, BankAccount other) {
        withdraw(amount);
        other.deposit(amount);
    }

    /**
     * Return the string representation of this account in the form
     *
     *     institution: $balance
     *
     * where the balance value is rounded to two decimal places.
     */
    public String toString() {
        return institution + ": $" + new DecimalFormat(".##").format(balance);
    }

    /**
     * Compare this account with the given other account, using balance as the
     * basis of comparison.
     */
    public int compareTo(BankAccount other) {
        if (balance < other.balance) return -1;
	if (balance == other.balance) return 0;
        return 1;
    }

}