CPT 388 - Java II

Spring 2001

Exercise 6:

Purpose:

To learn how to create object-oriented programs using BlueJ.

Background:

BlueJ is a Freeware tool created to assist students with learning Object-Oriented programming using Java. It can be downloaded from http://www.bluej.org.

To access BlueJ in the CNC labs, copy the batch file below into your working directory.

g:\pool\tprice\cpt388\bluej.bat

You can start BlueJ by running this batch file.

Procedure

Create an application that consists of three classes: BankAccount, CheckingAccount, and MyAccount. The properties for these classes are shown below:

public abstract class BankAccount
// instance variables
private double balance;
private String lastName;
private String firstName;

public BankAccount(String fname, String lname) // constructor
public void makeDeposit(double d)
public void debit(double d)
public double getBalance()
public String toString()

public class CheckingAccount extends BankAccount
private int accountNumber; // instance variable 

public CheckingAccount(String fname, String lname, int accountNumber, double deposit) // constructor
public void makeDeposit(double d)
public void processCheck(int checkNum, double d)

// the complete implementation of MyAccount is shown below
public class MyAccount
{
    public static void main(String[] args)
    {
        CheckingAccount c = new CheckingAccount("Tim", "Price", 22112, 100.0);
        System.out.println("Checking acount info: "+c);

        c.makeDeposit(200.0);
        System.out.println("Checking acount info: "+c);

        c.processCheck(1101, 50.0);
        System.out.println("Checking acount info: "+c);
    }
}

Running the program should generate the output shown below:

$100.0 deposited to account.
Checking acount info: Customer: Tim Price Balance: 100.0
$200.0 deposited to account.
Checking acount info: Customer: Tim Price Balance: 300.0
Check number 1101 processed for $50.0
Checking acount info: Customer: Tim Price Balance: 250.0

The class diagram in BlueJ is shown below:

Compile and run this program in BlueJ and make sure that the output is correct. Set a breakpoint in main() and single-step your program.