EX03 – Abstract Data Types!

0. Complete the Prerequisites

Before continuing on, make sure you’re caught up on the lectures through 5/21.

1. Download New Course Material

“Pulling” course materials down from Upstream. As new lesson material or starter code for exercises is added to our central course repository, these are the steps you’ll take to download them into your own workspace repository.

1. Open the Git menu from along the top and select Pull
   • This should open a pop-up that is auto-populated with the correct options. The correct command is git pull origin main. We are pulling code from the course source repo into our local repo.
2. This downloads the latest course materials! It will succeed silently, so if nothing appears to happen it worked (and any new files will be available in the file explorer). If there was an error, you would see an error message pop up.

You should see in your exercises src folder an ex03 package with a ComplexNumber interface and the ComplexNumberImpl class. This involves completing an implementation for the ComplexNumber Abstract Data Type. Your work will be going in the ComplexNumberImpl, where you will complete the implementation, filling in the concrete behavior.

2. Complex Number ADT

The package ex03 contains a Java interface for the complex number abstract data type. Refer here for a refresher on complex numbers:

https://en.wikipedia.org/wiki/Complex_number

Complete the implementation for the data type started in ComplexNumberImpl. The ADT is being modeled as an immutable type which means that the multiply and add methods should create new instances to return as their result.

Use the statically defined EQUALS_EPSILON as the epsilon bound for testing equality of the real and imaginary parts in your implementation of equals. The named constant I is also defined for your convenience if you should need it.

The functional specification of the ADT is as follows (7 methods):

1. create: DOUBLE x DOUBLE => COMPLEX

This notation is simply saying that there is a method that takes in two doubles, and returns a complex number.

Canonical operation for creating a new complex number given the magnitudes of its real and imaginary parts.

This corresponds to the Constructor method you will define and implement in your ComplexNumberImpl class.

2. real: COMPLEX => DOUBLE

Returns the magnitude of the real part.

This corresponds to the getReal method you will define and implement in your ComplexNumberImpl class.

3. imag: COMPLEX => DOUBLE

Returns the magnitude of the imaginary part.

This corresponds to the getImaginary method you will define and implement in your ComplexNumberImpl class.

4. absolute: COMPLEX => DOUBLE

Absolute value (see wikipedia page)

This corresponds to the getAbsoluteValue method you will define and implement in your ComplexNumberImpl class.

5. add: COMPLEX x COMPLEX => COMPLEX

Addition (see wikipedia page)

This corresponds to the add method you will define and implement in your ComplexNumberImpl class.

6. multiply: COMPLEX x COMPLEX => COMPLEX

Multiplication (see wikipedia page)

This corresponds to the multiply method you will define and implement in your ComplexNumberImpl class.

7. equals: COMPLEX x COMPLEX => BOOLEAN

Equality test. Two complex numbers are equal if both their real and imaginary parts are within EQUALS_EPSILON of each other.

This corresponds to the equals method you will define and implement in your ComplexNumberImpl class.

Your tasks:

1. Set up the necessary class fields in ComplexNumberImpl
2. Implement these 7 methods in ComplexNumberImpl

3. Make a Backup Checkpoint “Commit”

“Push” your work up to GitHub for backup. By creating “commits”, which you can think of as versioned checkpoints in your workspace, you are not at risk of losing your work. It’s easy to revert back to an old version or to restore your entire workspace on a different computer.

1. Select the Git menu along the top of your screen and then choose “Commit”.
2. Notice the files listed under Changes. These are files you’ve made modifications to since your last backup.
3. Ensure all the files that you’d like to backup are selected. Your cursor should be inside of a message box where you will write a nice description of the modifications you’ve made to your code, like “Finished EX03!”, and then hit the “Commit” button.
   • If you do not want to backup all changed files, you can select them individually. For this course you’re encouraged to back everything up.
   • IntelliJ might tell you there are some warnings or errors here, and you should just commit anyway!
4. If you open the Git at the bottom of your screen, you should see this commit added to your chain of git commits. However, it has just been added to your local main branch, and needs to be pushed to your remote backup.
5. Select the Git menu along the top of your screen again and then choose “Push”.
6. A pop-up should appear that displays: “main -> backup : main”, which means your latest local commit on the local main branch is going to be pushed to the main branch on the remote backup. If you see “main -> origin : main”, just click where it says origin and select backup. Hit the “Push” button.
7. If you want to see your backed up work on Github, navigate to the following URL but replace USERNAME with your GitHub username:
   • https://github.com/comp210-ss1-24/summer210-workspace-USERNAME
   • You can also verify it was pushed successfully by opening the Git view along the bottom of your screen and verifying the latest commit appears on the local and remote branches. (The text next to the tag icons should say backup & main, next to the latest commit message)

4. Submit to Gradescope for Grading

All that’s left now is to hand-in your work on Gradescope for grading!

Before doing so, you need to know that before an assignment’s deadline you can resubmit work as many times as you need to without penalty. Portions of assignments are autograded and will provide near-immediate feedback. We want you to resubmit as many times as it takes you in order to earn full autograding credit!

Login to Gradescope and select the assignment named “EX03 - ADTs You’ll see an area to upload a zip file. To produce a zip file for autograding, return back to IntelliJ.

Mac Users

Along the bottom of your window, you should see an option to open a terminal integrated into IntelliJ.

Type the following command (all on a single line):

./submit.sh ex03

In the file explorer pane, look to find the zip file named “ex03_submission.zip”. If you right click on this file “Open in -> Finder” on Mac, the zip file’s location on your computer will open. Upload this file to Gradescope to submit your work for this exercise.

Windows Users

We are working on rewriting the script to work for Windows! Until then, please navigate to your course workspace in a File Explorer window. Then right click on the src folder in your exercises directory and compress the directory into a zip folder. You can name it “ex03_submission.zip”

When you upload it to Gradescope, please delete any files that showed up in the src/ folder that were not actually part of ex03. You should include both the ComplexNumber Interface and ComplexNumberImpl Class in your zip.

Autograding will take a few moments to complete. For this exercise there will be no “human graded” component, but in future exercises and projects there will. Thus, you should expect to score 100 out of 100 possible points on this assignment. If there are issues reported, you are encouraged to try and resolve them and resubmit. If for any reason you aren’t receiving full credit and aren’t sure what to try next, come give us a visit in office hours!