CS 206 Assignment 3

CMSC 206 (Data Structures)

Assignment#3

Due: October 3, 2012 11:59:59pm

The goal of this assignment is to develop your ability to do object-oriented programming, focusing specifically on inheritance and code reuse.

Introduction

In this assignment, you will complete a program that allows a user to repeatedly create and manage credit card accounts. Your implementation should build directly on the CreditAccount class you created in the previous assignment.

You will write a program that allows a user to repeatedly create new credit accounts from three possible types: a standard account, a gold account, or a last-chance account.

A standard credit account has an annual interest rate of 1.25%, and an upper limit of $4,000.
A gold account has an annual interest rate of 0.08333% and an upper limit of $100,000. In addition, gold card holders earn 2% cashback on every purchase.
A last-chance account is for people with a bad credit history. The annual interest rate is 2.0833% and there is a $1,000 credit limit. However, a last chance card holder can get a better deal by consistently paying off the entire balance. If a last chance card holder pays off the balance three times in a row, then their interest rate drops to 1.6667% and their limit increases to $1,500. However, if they miss a payment (noted by a payment of 0), their interest rate will increase to 2.25%.

To begin, download these two files: Assignment3Skeleton.java and CS206Assignment3.jar. The first (java) file is skeleton version of the program; start with this file and fill in the parts marked as "FIXME" to complete the assignment. The second (jar) file is a completed version of the assignment that you can study. To run this completed program, use the command java -jar CS206Assignment3.jar


            Background on Credit Cards

When a new credit card account is opened, the credit company sets a credit limit for the user that specifies the maximum balance allowed on the account. Unlike a debit card, the balance starts at $0. The user can make purchases and charge them to the credit card, increasing the balance. For example, if I charge two purchases of $100 and $50, my credit card balance would be $150. Say that my credit limit is $500. If I then tried to charge another $400 purchase to the card, the card would be declined since that would put the balance over my credit limit. At the end of each month, the user must pay the entire balance on the card, or else the credit company charges the user interest on the balance.

Cashback (as given in the gold account) is money that the credit card pays you for making a purchase. For example, if you make a $100 purchase on the card and get 2% cashback, your balance would increase by $100 - $2 = $98.

Program Requirements

Starting with the skeleton file provided above, you will modify the two parts marked as "FIXME" to complete the assignment.

Complete the userMenu() function to properly display the options for interacting with a single account, following the menu format given below in the example trace. The skeleton file already provides examples of several menus that you can model to complete this task. Your function should use proper error checking on the inputs, especially when prompting the user for charge/payment amounts. Experiment with the demo program given in the jar file above, trying different inputs to see how the program behaves.

Notice that the CreditAccount class you created in Assignment 2 implements the standard credit account described above.

Implement classes for the gold and last-chance account that extend the CreditAccount and implement the appropriate behavior for each type of account. These subclasses should reuse as much as possible from the base CreditAccount class. If functionality is shared between all three account types, then it should be included in the CreditAccount class (i.e., don't implement the same thing three times in the subclasses, implement it once in the CreditAccount class). You may add constructors and protected setters to your CreditAccount class; however, you should not need to make any other changes to your CreditAccount class.

Be sure to do error checking on the inputs. Negative payments and charges are not allowed.

As in the previous assignment, all decimals need to be rounded off to two decimal places.

All of the provided code can be used as-is, except where noted explicitly in the file. In other words, you should not need to change anything in main, in any of the menu functions other than userMenu(), and the utility functions.

While you are free to be creative with some of the messages, you program must follow the same menu structure, the ordering of the options, and the effects of each button press. In other words, if I close my eyes at the main menu and then choose option 2, enter account number 0, then option 2, and then type 300, your program should do the exact same thing (charge the account $300) as the sample program. You can improve the look of the menu system, the wording of the messages, the formatting of the amounts (for example, make all dollar amounts be outputted to two decimal places), and the output details; just don't change the program functionality. If you do wish to add new features, you can add additional items to the end of any menu.

Here's an example trace of the program running once the assignment is complete.

Welcome to CS206 Credit
            Company

            

            MAIN MENU

            1.) Create a new account

            2.) Log into an existing account

            3.) Exit the banking system

            Please enter your selection: 1

            

            CHOOSE THE TYPE FOR THE NEW ACCOUNT

            1.) Standard credit account

            2.) Gold credit account

            3.) Last-chance credit account

            Please enter your selection: 1

            Created new standard credit account #0 with a credit limit
            of $4000.00

            

            STANDARD CREDIT ACCOUNT #0 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 2

            Enter charge amount: 1000

            Charged $1000.00        New balance
            $1000.00

            

            STANDARD CREDIT ACCOUNT #0 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 3

            Enter payment amount: 100

            Charged interest $12.50

            Received payment $100.00        New
            balance $912.50

            

            STANDARD CREDIT ACCOUNT #0 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 4

            Goodbye!

            

            MAIN MENU

            1.) Create a new account

            2.) Log into an existing account

            3.) Exit the banking system

            Please enter your selection: 1

            

            CHOOSE THE TYPE FOR THE NEW ACCOUNT

            1.) Standard credit account

            2.) Gold credit account

            3.) Last-chance credit account

            Please enter your selection: 2

            Created new gold credit account #1 with a credit limit of
            $100000.00

            

            GOLD CREDIT ACCOUNT #1 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 2

            Enter charge amount: 1000

            Received cashback reward of $20.00

            Charged $1000.00        New balance
            $980.00

            

            GOLD CREDIT ACCOUNT #1 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 4

            Goodbye!

            

            MAIN MENU

            1.) Create a new account

            2.) Log into an existing account

            3.) Exit the banking system

            Please enter your selection: 1

            

            CHOOSE THE TYPE FOR THE NEW ACCOUNT

            1.) Standard credit account

            2.) Gold credit account

            3.) Last-chance credit account

            Please enter your selection: 3

            Created new last-chance credit account #2 with a credit
            limit of $1000.00

            

            LAST-CHANCE CREDIT ACCOUNT #2 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 2

            Enter charge amount: 1000

            Charged $1000.00        New balance
            $1000.00

            

            LAST-CHANCE CREDIT ACCOUNT #2 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 3

            Enter payment amount: 0

            Charged interest $20.83

            Missed payment. Increasing interest rate to 27%.

            Received payment $0.00        New
            balance $1020.83

            

            LAST-CHANCE CREDIT ACCOUNT #2 MENU

            1.) Get a balance on your account

            2.) Charge your account

            3.) Make a payment

            4.) Log out

            Please enter your selection: 4

            Goodbye!

            

            MAIN MENU

            1.) Create a new account

            2.) Log into an existing account

            3.) Exit the banking system

            Please enter your selection: 3

            Exiting Banking System

Implementation Hints

Start by compiling and running the provided java file. It currently skips over the user menu, which you'll need to implement.

Also experiment with the provided demo in the jar file, noting how the menus work, how the program functions, and how input errors are handled.

Read over the java file in detail several times to ensure that you know how each line in the file works and what it does.

Rename the Assignment3Skeleton.java file to be named Assignment3.java

Next, implement the user menu. Instead of actually implementing the functionality, just have each menu option print out a string representing what it would do if it were implemented (e.g., "Made Payment", "Charge the Account", etc.)

Integrate your CreditAccount class into the program, slowing adding in functionality into the user menu and testing as you go. Do not try to integrate all functionality at once. Integrate one part, get it working, and then move on to the next.

Once the standard credit account works with the menu, move on to the GoldCreditAccount and LastChanceCreditAccount classes. Write main() methods in each of these classes to test their functionality (just like we did in the previous assignment) before you integrate them into the menu system. Compared to your CreditAccount class, these subclasses should be rather short.

Use good object-oriented design throughout the assignment, focusing especially on code re-use. Always try to reuse functionality from the superclass, keeping the subclasses as minimal as possible.

Test your Credit Account Manager application thoroughly.

Submitting the Assignment

Be certain that all files contains proper header comments that include your name.

Place all .java and compiled .class files into a directory entitled LastnameFirstname-Assignment3. This includes your CreditAccount.java and CreditAccount.class files from the previous assignment.

Make certain that your assignment will run when the command java Assignment3 is called from the terminal.

Compress the LastnameFirstname-Assignment3 folder as a zip or tar file, and submit it via Dropbox, as detailed in the assignment submission instructions.