/**
   An account that earns interest at a fixed rate.
*/
public class SavingsAccount extends BankAccount
{
   private double interestRate;

   /**
      Constructs a bank account with a given interest rate.
      @balance initialBalance the initial balance
      @param rate the interest rate
   */
   public SavingsAccount(double initialBalance, double rate)
   {
      super(initialBalance);
      interestRate = rate;
   }

   /**
      Adds the earned interest to the account balance.
   */
   public void addInterest()
   {
      double interest = getBalance() * interestRate / 100;
      deposit(interest);
   }

   // This method checks your work.  Do not modify it.

   public static double check(double initialBalance, double rate)
   {
      SavingsAccount account = new SavingsAccount(initialBalance, rate);
      account.addInterest();
      return account.getBalance();
   }
}