e careful to implement the steps of each

© Anthony W. Smith, 2016
CSCI 114 Programming Fundamentals II
Lab 5 Inheritance

Lab 5 Inheritance

Purpose
Purpose is to practice using regular inheritance.

The Checking superclass
First design, code and test a class called Checking. This will be your superclass.
Use exactly and only these instance variables:
private String accountID
private int balance
private int numDeposits
private int numWithdrawals
private double annualRate
private int serviceCharge

-an identifying account number e.g. “123”
-balance of the account in pennies, to avoid floating
point round-off errors e.g. 100 means $1.00
-number of deposits made this month
-number of withdrawals made this month
-annual interest rate e.g. 0.15 means 15% per
annum
-maintain the total monthly service charges incurred
here, in pennies

Checking will have the following methods. Be careful to implement the steps of each

method in exactly the order given below:

constructor
-has parameters for the account ID, starting balance (in dollars) and annual interest rate
-must initialize all instance variables
-use the following to convert the dollar starting balance parameter bal to cents, avoiding
round-off error:
balance = (int) Math.round(bal * 100.0);

appropriate get and set methods
-you have to decide during design what get and set methods are required
deposit()

-has a parameter for the deposit amount in dollars
-make the necessary conversion then add the amount to the balance
-increment the number of deposits
-add a deposit fee of 10 cents (in pennies) to the monthly service charge

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© Anthony W. Smith, 2016
CSCI 114 Programming Fundamentals II
Lab 5 Inheritance

-note that the deposit fee is NOT deducted from balance at the time of the deposit
transaction
-(use static final constants for all the fee amounts)
withdraw()

-has a parameter for the withdrawal amount in dollars
-make the necessary conversion then subtract the amount from the balance
-increment the number of withdrawals
-add a withdrawal fee (in pennies) to the monthly service charge:
-the first 2 withdrawals cost 25 cents each
-withdrawals after the first 2 cost 75 cents each
depositInterest()

-update the balance by calculating the monthly interest earned on the account, then add
this interest to the balance. In pseudocode:
monthly interest rate = annual interest rate / 12.0
monthly interest = balance * monthly interest rate
balance = balance + monthly interest
-(use Math.round() where necessary to prevent rounding errors)
printMonthEnd()

-run at the end of the month to first add interest, then deduct monthly service charges,
than summarize the account. In pseudocode (implement these actions in exactly this
order):
call the depositInterest() method
add a monthly fee of $1.00 to the monthly service charge
decrease the balance by the total monthly service charge
output the account ID, resulting balance, number of deposits and withdrawals and the
monthly service charge (use printf() to output monetary amounts in dollars, with 2
decimal places)
set the number of deposits and withdrawals and monthly service charge to zero
-an example of the printMonthEnd() output format:
Account ID 123
Balance is: $751.88
1 deposits, 3 withdrawals
Monthly service charge was: $2.35

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© Anthony W. Smith, 2016
CSCI 114 Programming Fundamentals II
Lab 5 Inheritance

toString()
-return a String that represents the Checking object, must be in standardized formatting

e.g.
Checking[accountID=123, balance=74800, numDeposits=1, numWithdrawals=3,
annualRate=0.1, serviceCharge=135]

The MoneyMarket subclass
Next design, code and test a MoneyMarket subclass that inherits from Checking.
MoneyMarket instance variable:
active

a boolean variable that maintains the status of the account. Status is
defined as active if the balance is greater than a minimum balance of
$500.00, otherwise is not active. Account status must be updated
every time the account balance is changed. Withdrawals are not
allowed if the account is not active, until deposits make the account
active again

MoneyMarket will have the following methods Be careful to implement the steps of

each method in exactly the order given below:

constructor
-has parameters for account ID, the starting balance (in dollars) and annual interest rate
-use the superclass constructor to set these
-then set whether the account is active or not active
withdraw()

-output a message in the following format if the account is not active, and done:
MoneyMarket 456: Withdrawal not allowed

-otherwise call Checking withdraw() (use super to do this), then must update the status
of the account
deposit()
-call Checking deposit() (use super to do this), then must update the status of the

account
printMonthEnd()

-run at the end of the month to add interest, deduct monthly service charges and
summarize the account. In pseudocode (implement these actions in exactly this order):

3

© Anthony W. Smith, 2016
CSCI 114 Programming Fundamentals II
Lab 5 Inheritance

add a minimum balance fee of $5.00 to the monthly service fee if the account is not
active
call Checking monthEnd() (use super to do this)
update status of the account
output the status of the account e.g.
"Money market account is: active" or
"Money market account is: inactive"

-an example of the printMonthEnd() output format for the MoneyMarket class:
Account ID 456
Balance is: $296.15
1 deposits, 1 withdrawals
Monthly service charge was: $6.35
Money market account is: inactive

toString()
-return a String that represents the MoneyMarket object, must be in standardized

formatting e.g.
MoneyMarket[accountID=456, balance=30000, numDeposits=1,
numWithdrawals=1, annualRate=0.1, serviceCharge=35][active=false]

The Tester class
The Tester class tests your new Checking and MoneyMarket classes. Source code for
Tester is given below, and can be downloaded from Blackboard, Course Documents,
Week 12, Example programs.
import java.util.ArrayList;
/**
* Driver for Lab 5 Inheritance
*
* @author Anthony W. Smith
* @version 5/31/2028
*/
public class Tester
{
public static void main(String arg)
{
// create some accounts
// $100.00, 10.0% annual interest
Checking check = new Checking("123", 100.0, 0.1);
// $1000.00, 10.0% annual interest
MoneyMarket money = new MoneyMarket("456", 1000.0, 0.1);

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© Anthony W. Smith, 2016
CSCI 114 Programming Fundamentals II
Lab 5 Inheritance

ArrayList<Checking> accounts = new ArrayList<>();
accounts.add(check);
accounts.add(money);
// do some transactions
System.out.println("Transactions");
// on Checking object
check.deposit(750.0);
check.withdraw(12.0);
check.withdraw(34.0);
check.withdraw(56.0);
// on MoneyMarket object
money.withdraw(750.0);
money.withdraw(100.0);
money.deposit(50.0);
// print accounts
System.out.println(" Print accounts");
for (Checking c : accounts)
System.out.println(c.toString());
// print month end report
System.out.println(" Month end report");
for (Checking c : accounts) {
c.printMonthEnd();
System.out.println();
}
}
}

Hints
first, take a calculator and work carefully through Tester line by line, writing down
on a piece of paper the values of the instance variables that should be produced…

this makes sure you understand what every method does, and gives you the expected
output you need to test your program

now design your new Checking and MoneyMarket classes on a piece of paper

use inheritance – a MoneyMarket account is-a Checking account, with an account
status added

design algorithms, think about parameters and return values

then use BlueJ as usual to code and test each method in turn. Comment out in Tester
the methods you have not yet implemented

5

© Anthony W. Smith, 2016
CSCI 114 Programming Fundamentals II
Lab 5 Inheritance

Required
Tester in your final submission must not be changed in any way

every method must have a clear, meaningful Javadoc comment

each toString() is required to use standardized formatting

automatically and routinely use all the other components of simplicity and clarity, as
listed in Blackboard, Course Information, “How labs are graded”

when you have thoroughly tested your program and are certain it is correct, save your
output into the output.txt file

Lab 5 submission
deadline for this lab is 3 weeks, by end of Sunday 5/1

zip your BlueJ project plus output.txt output file and email to me at
awsmith@palomar.edu
you will lose points if you do not include a file named output.txt containing the
output of your program

your email Subject line must say ‘CSCI 114 Lab 5’ followed by your full name, so
that it filters to the correct email folder for grading
you will lose points if you format your email Subject incorrectly
e.g. my email Subject would be:
CSCI 114 Lab 5 Anthony W. Smith

this is a graded lab, so a reminder that you may not copy code from other people

reminder that late labs will be penalized 2 points per week or part of week late

6

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