Write a BankAccount class that keeps track of the balance of a bank account. There should be two constructors–one that creates an empty bank account (with a balance of 0), and one that creates a bank account with some specified amount of money in it (indicated as a parameter in the constructor).
There are three methods for this class: deposit(amount), withdraw(amount), and getBalance().
After writing the BankAccount class, write BankAccountTester.java and, in its main() method, constuct a couple of bank accounts and demonstrate how the methods work.
The BankAccountWithInterest class has an additional method addInterest(rate) which adds money earned as interest to the balance.