Lab 01: Setup | CS 61B Fall 2023 (2024)

FAQ #

Each assignment will have an FAQ linked at the top. You can also access it byadding “/faq” to the end of the URL. The FAQ for Lab 1 is locatedhere.

Welcome to CS 61B! #

We’re very excited to work with you this term! Before we can get started, you’llneed to have a computer that you can work on assignments on. In this class,you’ll be using real-world tools, which means that you’ll likely run intoreal-world problems. These are hard problems, and software engineers run intothem every day! Don’t be discouraged, and make sure to askfor help if you’re stuck!

We highly recommend attending a lab section, and asking for help during labsection. If you’re working outside of a lab section, you can ask on Ed orattend office hours.

WARNING: If something isn’t working, do not keep trying random things! Instead, ask for help. Your lab TA will tell you how to join the queue. They may choose to use a whiteboard queue or the online OH queue.

In general, while you are waiting, you should move on to the next step of theassignment, whenever possible.

Partners #

Labs in CS 61B are solo. This means that you will need to write and submityour own code. For Lab 1 in particular, you will need to set up your owncomputer.

However, we strongly encourage working togetherwith other students! In-person lab sections are an excellent place to findgroups.

Goals and Workflow #

In this lab, we will work on setting up the software that will be used throughout this course. This includes an introduction to the terminal, git, Java, and IntelliJ. We’ll also work through a small Java program to get situated with the Java language!

INFO: This lab will be long! To help guide you through this lab, here’s a brief overview of what your workflow should look like:

Installing Software (Java, Git, Gh)
Terminal Tasks
Setting Up Github and Beacon Accounts
Git Basics and Exercises
Setting Up Your Git Repository and Libraries (IMPORTANT!)
Submitting to Gradescope
IntelliJ Setup and Java Deliverable
Final Deliverables (magic_word.txt and Arithmetic.java)

Do not skip steps!

Personal Computer Setup #

Task: Installing Software #

Installation will vary, depending on your operating system.

Windows instructions
macOS instructions
Linux instructions

TASK: Follow the guide for your operating system to install the software.

The Terminal #

Terminal Guide #

In CS61B, we will be using the terminal extensively to work with git. The terminal also has some other commands that allow you to work with folders or files. We’ve compiled them in this brief guide, so please make sure to readthrough it here: How to Use the Terminal.

TASK: Read through the terminal guide!

Task: Terminal Test Run #

Let’s ensure that everything is working.

First open up your terminal.Check that git is a recognized command by typing the following command:
```
git --version
```
The version number for git should be printed. If you see “git: command notfound”, or similar, try opening a new terminal window, restarting yourcomputer, or installing git again.
Second, let’s check that javac and java are working.javac and java allow Command Line Compilation, or in other words,the ability to run Java programs directly from the command line.In practice, most developers run Java programs through an IDE like IntelliJ,so we won’t be using command line compilation this semester other thantesting your setup.

Start by running the following commands at your terminal.
```
mkdir ~/tempcd ~/temp
```
1. Then, open your operating system’s file explorer in this directory.You can do this from the command line:
  - Mac: open .
  - Windows: explorer .
  - Ubuntu: gnome-open .
2. In this newly opened directory, create a file HelloWorld.java withthese contents:
```
public class HelloWorld { public static void main(String[] args) { System.out.println("Hello world!"); }}
```
  Note that in addition to the file finder or explorer, you are able tocreate a file using the touch in the terminal; try creating the fileusing touch HelloWorld.java from the terminal! Then, open the fileusing your favorite text editor and copy-paste the code.
3. In your terminal, enter ls (list the files/folders in this directory).You should see HelloWorld.java listed.
4. Run javac HelloWorld.java. If this produces any output, then somethingmay be wrong with your setup. Try opening a new terminal window orrestarting your computer. If that still doesn’t work, see theTroubleshooting section under the directions for your operating system.
5. Type ls, you should see both HelloWorld.javaand a freshly created HelloWorld.class (the javac command createdthis file).
6. Run java HelloWorld. It should print out “Hello world!” for you.If it didn’t, something is wrong with your setup!
7. You’re done! You can also delete the “temp” folder and its contents asyou please.

The screenshot below shows what we’re hoping for when we do the above steps.If you see something similar to this, your terminal setup is complete.

TASK: Familiarize yourself with the terminal and complete the steps mentioned above.

GitHub and Beacon Accounts #

Overview #

Instead of bCourses, CS 61B uses an in-house system for centralizing yourgrades and student information called Beacon.

In this section, we’ll set up your Beacon account as well as your CS 61B GitHubrepository (“repo”), which you will need to submit all coding assignments.

Task: Setting Up Accounts #

Create an account on GitHub. If you already havean account, you do not need to create a new one.
Go to Beacon and follow the steps to complete your GitHub repositoryregistration. You must be logged in to your Berkeley account to completethe Google Form syllabus quiz.
After completing all of the steps, you should receive an email inviting youto collaborate on your course GitHub repository. Accept the emailinvitation to receive access to your course repository. This email will besent to the email that you used to create your GitHub account, which maynot necessarily be your Berkeley email.

WARNING: Don’t follow the instructions that GitHub says you might want to do.We have our own set of instructions later in this lab.

TASK: Follow the steps above to create your GitHub and Beacon accounts, andconnect them.

Your Repository #

Your repository will have a name containing a number that is unique to you.For instance, if your repo is called “fa23-s1”, you’ll be able to visit yourprivate repository at https://github.com/Berkeley-CS61B-Student/fa23-s1(when logged into GitHub). Your student number is not “1”, so thislink will not work for you. Replace “1” with your own number to see your repo onGitHub.

Additionally, course staff will be able to view your repository. This means you can (and should!) link to your code when asking private debugging questions in Ed or Gitbugs. No other students will be able to view your repository.

WARNING: As a reminder, you may not post code from this course publicly, even aftercompleting the course. Doing so is a violation of our course policies and youmight be subject to disciplinary action.

Git #

Git Basics #

In this course, you’ll be required to use the Git version control system, whichis nearly universal out in the real world. Since the abstractions behindit are fairly tricky to understand, don’t be worried if you encountersignificant frustration as you learn to use it.

TASK: Before you proceed, read up to the Remote Repositoriessection of the Using Git Guide. You do not needto read past that.

Task: Setting Up Git #

Before we use git, we have some short commands to configure it appropriately.

First, set the name and email that git will use with these two commands:

git config --global user.name "<your name>"git config --global user.email "<your email>"

Set git’s default branch name:

Task: Git Exercise #

Now you’re ready to start using git! Your next task is to work through a smallgit workflow by setting up a repository and making a couple commits. At the end,you will need to be checked off by filling out the form linked on Beacon.

INFO: If you need help with creating directories, creating files, changingdirectories, etc., refer back to How to Use the Terminal. Anotherresource that might be helpful is Section C of the Using Git Guide.

As a quick recap, you may find the following git commands useful: git init, git add, git commit, git status, git log, git restore.

Create a directory called lab01-checkoff. You can put this directoryanywhere on your computer (unless you have already cloned your fa23-s***repository, in which case, you should not put this directory insideyour fa23-s*** repo).
Move into the lab01-checkoff directory, and initialize a git repository.
Create a file called 61b.txt in any way you’d like. In this text file,add the text “Created 61b.txt”.
Create another file called 61boba.txt in any way you’d like. In this text file, add the text “Created 61boba.txt”.
Begin tracking only 61b.txt, and create a new commit containing justthis file, with the following commit message: Add 61b.txt.
Make a modification in 61b.txt by changing the text in the file to: “61b.txtchanged to version 2”.
Make another commit, this time containing both 61b.txt and 61boba.txt.The commit message should be: Updated 61b.txt and added 61boba.txt.
Make one more modification to 61b.txt by changing the text inthe file to: “61b.txt changed to final version”. Don’t commit this version.

At this point, if you were to type in git status and git log, you’d seesomething similar to the following:
Using git only, restore 61b.txt to the version in the most recentcommit.
Using git only, restore 61b.txt to the version in the first commit.

Be sure to save this repository and directory until you complete theasynchronous checkoff form on beacon andobtain a magic word.

TASK: Do the steps above, then get checked off by filling out the Beaconform.

Git and Remote Repos #

First, read the Remote Repositories section of theUsing Git Guide.

In this course, you’ll be required to submit your code using git to your courseGitHub repository that you created in Account Setup.This is for several reasons:

To spare you the incredible agony of losing your files.
To submit your work for grading and to get results back from the autograder.
To save you from the tremendous anguish of making unknown changes to yourfiles that break everything.
To ensure that we have easy access to your code so that we can help ifyou’re stuck.
To dissuade you from posting your solutions on the web in a public GitHubrepository. This is a major violation of course policy!
To expose you to a realistic workflow that is common on every major projectyou’ll ever work on in the future.

Task: Git Repository and Java Libraries #

Java Libraries #

Like in Python, we sometimes want to use libraries that others wrote. Java dependency management is a bit of a mess, so we instead provide a git repo that contains all the dependencies that we will use in this course.

Navigate to the folder where you would like to store your libraries. For this lab, we’ll assume that you placed all your stuff in a folder named cs61b. You can pick a different nameif you would like to.

To go into that folder, cd into it:

cd cs61b

Once inside the folder, run:

git clone https://github.com/Berkeley-CS61B/library-fa23

Below is the directory structure of library-fa23. Look inside the folder using ls library-fa23 and make sure you see the .jar files listed below. There are many more, but we only list the first few. If you’re using your operating system’s file explorer, the jar part might not show up in the filenames, and that’s OK.

library-fa23├── algs4.jar├── animated-gif-lib-1.4.jar├── antlr4-runtime-4.11.1.jar├── apiguardian-api-1.1.2.jar└── ...

TASK: Follow the instructions above to get the course libraries.

Configure Personal Repository #

Now, it’s time to clone your personal repository. As you did with the libraries, navigate to the folder where you would like to keep your repository. We recommend that it’s the same folder as whereyou stored your Java libraries (for example, cs61b).

Before we do clone your repo though, we need to login to Github. Verify that you have the Github package:

gh --version

You should see a version number displayed. If you instead see a command not found error, please install Github cli again by following the steps outlined for you operating system.

Next login with your account with the following command:

gh auth login

You’ll be asked a few questions with some options to select from. You don’t have to worryabout them, simply select the first options for all of them and proceed. You’ll be providedwith a one time code, and prompted to open the browser.

Enter the code in the browser window and select authorize Github. You should now be logged in!

NOTE: For Windows Users: if you run into an error that says “could not prompt: Incorrect Function”, run winpty gh auth login instead.

The entire process should look like the below:

Once you’ve logged in, run the following command to clone your personal repository. Make sure to replace the *** with your class repository number (you can find this repo number on Beacon).

WARNING: Do not place your repository inside the library-fa23 folder. This will cause headachesin the future.

git clone https://github.com/Berkeley-CS61B-Student/fa23-s***.git

INFO: After cloning your terminal will report warning: You appear to have clonedan empty repository. This is not an issue, it is just git letting you knowthat there are no files in the repo.

Move into your newly created repo!

cd fa23-s***

Getting the Skeleton #

TASK: Follow the instructions in theGetting the Skeleton section of the Assignment Workflow guideto get the skeleton code for Lab 1.

WARNING: At this point, you should have a lab01 folder, with the contentssrc/Arithmetic.java and tests/ArithmeticTests.java. If you do not havethese contents, don’t make it manually! Instead, pull from the skeleton orask a staff member.

Pushing to GitHub #

NOTE: You will need the magic word (obtained from checkoff) to complete thisstep.

Open the file lab01/magic_word.txt in a text editor, and edit it to containthe magic word obtained during the git exercise.

Now stage and commit magic_word.txt (make sure you’re in your fa23-s*** repo!).

git add lab01/magic_word.txtgit commit -m "Added Magic Word"

Right now, the modified magic_word.txt is only on your computer. We want topush these changes to the GitHub repository so that your changes can be seen byus and Gradescope. Push these changes to the main branch on the originremote repo.

git push origin main

You can verify that this was successful by checking your repository online onGitHub’s website. It should contain the updated magic_word.txt file. If itdoesn’t, make sure that your add and commit were successful. In particular,make sure that you are in your repo, fa23-***.

TASK: Follow the instructions above to push your magic word to GitHub, andcheck that it appears.

Our work is now on GitHub, and ready to submit!

Task: Submitting to Gradescope #

Although we use GitHub to store our programming work, we use Gradescope toactually grade it. The last step is to submit your work with Gradescope,which we use to autograde programming assignments.

INFO: We added everyone’s CalCentral email to Gradescope on the first day of labs.Make sure to login using the email address listed on CalCentral.

If you’re having trouble accessing the course on Gradescope or would like to usea different email address, ask your TA!

WARNING: As above, we strongly encourage you to make frequent commits! Lack ofproper version control will not be considered an excuse for lost work,particularly after the first week.

TASK: Follow the instructions in theSubmitting to Gradescope section of the Assignment Workflow guideto submit to Gradescope.

Once you submit, open this dropdown. No, you’re not done with the lab yet.

At this point, Gradescope should show you something similar to the following:

In CS 61B, we use automated tests to check that your code is written correctly.In your first submission, you:

Should be passing “Magic Word”, if you received the magic word
Should be passing “Test product correctness”
Should not be passing “Test sum correctness”

We’ll now show you how you can work on and check your code locally, which ismuch easier than checking on Gradescope every time.

Task: IntelliJ Setup #

IntelliJ is an Integrated Development Environment or IDE. An IDE is a singleprogram which combines typically a source code editor, tools to compile and runcode, and a debugger. Some IDEs like IntelliJ contain even more features suchas an integrated terminal and a graphical interface for git commands. Finally,IDEs also have tools like code completion which will help you write Java faster.

We highly recommend using IntelliJ. Our tests are written to runin IntelliJ, and we will explicitly use its debugger in later labs.Additionally, IntelliJ is an industry-standard tool that you will almostcertainly encounter if you work with Java again in the future.

We will assume that you are using IntelliJ, and will not offer support forother editors, including VSCode.

WARNING: IntelliJ is a real world, industrial software development application. There aremany features that we will not use, and you will sometimes encounter situationsthat do not make sense. Ask for help if you are stuck or something seemsbroken! It can be very hard to guess the right thing to do in IntelliJ. Checkout the IntelliJ WTFS Guide for solutionsto some common problems.

Before continuing, make sure that you have completed all above tasks besidesthe git exercise:

You have installed Java 17 or higher.
You have successfully created your local repo for the class on your ownmachine. This is the fa23-s*** repository you earlier.
You have pulled from the skeleton, and you have a lab01 directory.

Installing IntelliJ #

Download the Community Edition of IntelliJ from theJetBrains website.As a student you can actually get a student license for the Ultimateversion, but there are not any additional features that we will use for thisclass. It is recommended and assumed that you proceed with the CommunityEdition. The Ultimate Version will be the first one you see when you click on the link - make sure to scroll down for the Community Version.

NOTE: If you have an M1 or M2 Mac, select “.dmg (Apple Silicon)”. Otherwise, select “.dmg (Intel).”

After selecting the appropriate version for your OS, click download and waita few minutes for the file to finish downloading.
Run the installer. If you have an older version of IntelliJ, you shoulduninstall it at this time and replace it with this newer version.

INFO: While IntelliJ downloads, you can read / skim ourUsing IntelliJ Guide.You don’t need to read or internalize all of this to complete the lab.IntelliJ is complicated, but the core features should feel somewhat familiarto text editors you have used in the past.

Installing Plugins #

Open IntelliJ. Then follow the steps below.

Make sure you’re running IntelliJ Version 2021.2 or later beforecontinuing. This is because we will use Java 17 or later.We are using IntelliJ Version 2023.2 (in the images), which has an updated user interface. Note that there might be older screenshots of IntelliJ in this lab - that is fine since the general layout is still relatively consistent.

In the Welcome window, click the “Plugins” button in the menu on theleft.
On the window that appears, click “Marketplace” and enter “CS 61B” in thesearch bar at the top.The CS 61B plugin entry should appear.If you click the autocomplete suggestion, a slightly different windowfrom what is shown below may appear – this is okay.
Click the green Install button, and wait for the plugin to download andinstall.

If you have the plugin installed from a prior term, make sure to update it.
Now, search for “Java Visualizer”, and click the green Install button toinstall the plugin.
Restart (close and reopen) IntelliJ.

For more information on using the plugins, readthe plugin guide.You don’t have to read this right now.

Creating Projects #

TASK: Follow the instructions in theOpening in IntelliJ section of the Assignment Workflow guideto open lab01.

Once you’ve done this, you should see at least these three files in the leftpane:

magic_word.txt, which should contain the magic word you added.
src/Arithmetic, a Java file which contains your first programmingexercise.
tests/ArithmeticTest, another Java file which will check thatArithmetic is implemented correctly.

When you open Arithmetic and ArithmeticTest, you should not see any redtext or red squiggles.

IntelliJ Test #

To test if everything is working correctly, run the Arithmetic class byopening the file, clicking on the green triangle next topublic class Arithmetic, then clicking “Run ‘Arithmetic.main()’”.

There are other ways to run the main method.

Assuming that the file has a main method, you can right click on the file in the project view and navigate to [filname].main(). You can also run it through the green arrow in the top right (outlined in red).

You should see a console pop up, prompting you to enter a number:

If you follow the prompts, you will (probably) see something wrong! Don’t fixit yet.

Testing Your Code #

While we could run the Arithmetic file again and again to check that ourcode works correctly, it would take a lot of time to type into the program eachtime, and manually check that the output is correct. Instead, we use tests.

Open ArithmeticTest, and click the green triangle(s) next to thepublic class ArithmeticTest. This will run the tests that we have providedin this assignment. At this point, you will see the following:

The green checkmark () indicatestests that you have passed, while the yellow X() indicates tests that you havefailed. Don’t worry about the doubled output; this is a strange quirk ofIntelliJ.

INFO: This should look familiar. The test that failed on Gradescope is the same testthat we see here! We can run these tests locally, very easily!

TASK: Fix the bug in Arithmetic.java so that the tests pass.

Task: Saving Your Work using Git and GitHub #

As you are making changes to your code, it is good practice to save your workoften. We have briefly discussed the commands, but now we will explain how theyshould be used in practice. In the case that you ever want to go back toanother version of your code, it is better to have more options to roll backto. The next set of instructions will talk you through git’s version of savingwork through snapshots of your file system called commits.

After you have made some changes to the code within our local repository,git will take notice of these changes. To see the current stateof your local repository, use the command git status. Run this and try tointerpret the results. Do they make sense to you or do they match yourintuition? It is a good habit to run this before running other git commandsto know what the state of things are.
To save work that we have completed on a file, we first stage the file, andthen we can commit it. We stage a file with the command git add. Thisdoes not save the file, but it marks it to be saved the next time youcommit. The two below commands show what saving work looks like in a gitrepository. For git add depending on what directory you are in, the pathto the file you are adding might differ (use git status to see the path).

The -m "Completed Arithmetic.java" part of the commit command specifies amessage to be attached to this snapshot. You should always have a commitmessage to identify what exactly happened in this commit. As an exampleworkflow:
```
git add lab01/src/Arithmetic.javagit commit -m "lab01: Completed Arithmetic.java"
```
If you run git status, you will see thatYour branch is ahead of 'origin/main'. You will also see that thestaged changes are no longer staged, and are instead committed. If youhaven’t edited since staging, you shouldn’t have any changes not stagedfor commit.
We want to push these changes to the GitHub repository so thatyour changes can be seen by us and Gradescope. Your changes will also beavailable to pulled if you had your repo initialized in other places orother computers.
```
git push origin main
```
git status will now show thatYour branch is up to date with 'origin/main'.

WARNING: Get into the habit of saving your files and doing the git commit step often(i.e. every 15 minutes). It will be incredibly helpful when you mess things up,since it allows you to back out of changes and to see what you have changedrecently.

Basically, right when you sit down to work in your repository, first git pullto make sure you are starting with the most recent code. While you are working,frequently commit. When you are finished, git push so all your changes areuploaded and ready for you to pull again next time.

TASK: Follow the instructions (again!) in theSubmitting to Gradescope section of the Assignment Workflow guideto submit to Gradescope. This time, you should receive a full score on the lab.

Deliverables #

As a reminder, this assignment has an FAQ page.There are two required files, all inside the lab01 directory:

magic_word.txt: You should have received the correct magic word from completing the gitcheckoff.
Arithmetic.java: You should have fixed the bug so that the tests pass. We check this filewith an autograder! For this lab, the autograder tests are the same as theones you have on your computer.

Be sure to submit again according to thesubmission section, so that you submit yourcompleted lab. Congratulations on finishing your first CS 61B lab!

Optional: Josh Hug’s Color Schemes #

Per Josh Hug:

I’m not a big fan of the default IntelliJ colors.

Sunburst: If you want the color scheme that is used in most of the lecture videos,this is a custom color scheme I made which is a very close imitation of the great Sunburst themefor Sublime. To use Sunburst, download hug_sunburst, andimport it using the “File → Manage IDE Settings → Import Settings”option in IntelliJ. You might end up with large text, which I use forrecording videos. To adjust the size of the font in Intellij to your liking,seethis link.

Mariana Pro: In 2022, I switched over to Mariana Pro. It doesn’t feel as much likebeing in a forest as Sunburst, but it has more color depth. To get Mariana Pro, go to thesame plug-in shop that you used to install the CS 61B plugin, and search for “Mariana Pro”.This plugin was made by Thibault Soulabaille. Note that I prefer a pure black background,whereas Mariana Pro is a dark grey. You can change the background color using these directions.