Exercise 3.4

package bankaccounttester;

public class BankAccount
{
        private double balance;

        public BankAccount()
        {
                balance = 0;
        }
        /**
         * Constructs a bank account with a given balance
         * @param initialBalance the initial balance
         */
        public BankAccount(double initialBalance)
        {
                balance = initialBalance;
        }
        /**
         * Deposits money into the bank account
         * @param amount the amount to deposit
         */
        public void deposit(double amount)
        {
                balance = balance + amount;
        }
        /**
         * Withdraws money from the bank account
         * @param amount the amount to withdraw
         */
        public void withdraw(double amount)
        {
                balance = balance - amount;
        }
        /**
         * Gets the current balance of the bank account.
         * @return the current balance
         */
        public double getBalance()
        {
                return balance;
        }
        /**
         * Adds interest to the current balance of the account.
         * @param rate
         */
        public void addInterest(double rate)
        {
                balance = balance *(1+rate);
        }
}