4. Objects and Classes (1)
Lab Exercise 4-2: Create a Simple Banking Package
This exercise will introduce you to the banking project which we will return
to in several labs. This project will (eventually) consist of a bank with several
customers with several account each and a report. These classes will evolve
over the next lab exercises.
In this exercise, you will create very simple version of the Account
class. You will place this source file in the banking package. A test
program, TestBanking, has been written in the default package that
creates a single account. It initializes the balance of that account and performs
several simple transactions. Finally, the test program displays the final balance
of the account.
Start by changing your working directory to lab4/exercise2 on your
- Create the banking directory in your working directory.
- Create the Account class in the file Account.java
under the banking directory. This class must implement the model
in the above UML diagram.
- declare one private object attribute: balance; this attribute
will hold the current (or "running") balance of the bank account
- declare a public constructor that takes one parameter (init_balance);
that populates the balance attribute
- declare a public method getBalance that retrieves the current
- declare a public method deposit that adds the amount
parameter to the current balance
- declare a public method withdraw that removes the amount
parameter from the current balance
- Compile the given TestBanking.java file. This has a cascading
effect of compiling all of the classes used in the program; thus compiling
the Customer.java and Account.java files under the banking
javac -d . TestBanking.java
- Run the TestBanking class. You shoud see the following output:
Creating an account with a 500.00 balance.
The account has a balance of 324.88