int getBalance()
Other names for the method would also work, of course.
The method returns the current balance, which is an int
so the return type is int.
The method does not need any input data,
so its parameter list is empty.
You still need to have the two parentheses ( ) even though there
is nothing inside of them.
So far, the class looks like this:
All getBalance() needs is a statement that returns the
balance of the checking account.
Complete the method by filling in the blank.