During March and April of this year, I coordinated and taught a C++ Project Design workshop at Bergen Community College. This serves as an introduction to programming in C++, as well as some introduction to Linux and software development ideologies, such as Agile.

This was a four-part workshop, each lesson an hour long.

This post contains the first lesson of the workshop.

Workshop Outline

1. Setup (today!)
2. Programming fundamentals
3. Project introduction
4. Software methodologies

Today’s Outline

1. Install Linux on a VM (if necessary)
2. Install Git and VS Code
3. Create a GitHub account
4. Write commit messages and comments
5. Know parts of a computer, compilation, how to create a program

1. Install Linux 🐧

If you already use Linux or MacOS, hang tight! This is for Windows users.

1. Download VirtualBox
2. Download the ISO image for Xubuntu

Setting Up a New Virtual Machine in Virtual Box

1. Upon opening VirtualBox, hit New to create a VM.
2. Be sure to select the Xubuntu ISO image for ISO Image.
3. Uncheck Proceed with Unattended Installation.

4. Allocate your Base Memory (at most half of your total RAM) and 2 CPUs.
5. Allocate at least 30 GB for your virtual hard disk.
6. Select Finish.

7. Click Settings > Expert > Display
   • Enable 3D Acceleration
   • Increase Video Memory to 256 MB (the max)

Setting Up Xubuntu 🐀

Follow the on-screen instructions when installing Xubuntu!

Post Installation Steps

1. Open the terminal with CTRL + ALT + t and enter the following:

   sudo apt update
   

2. Now, upgrade your packages:

   sudo apt upgrade
   

3. Install two packages, which will help us install Guest Additions (that’ll help Xubuntu use the VM’s hardware):

   sudo apt install build-essential dkms
   

4. Install Guest Additions: Devices > Insert Guest Additions CD image... and find VBoxLinuxAdditions.run. In your terminal, type sudo and then drag VBoxLinuxAdditions.run into the terminal. Hit ENTER to install the Guest Additions.

5. Reboot with sudo reboot. You should have less lag or performance issues now!
6. Eject the Guest Additions image.

2. Install Git and VS Code

On Linux

Open the terminal with CTRL+ALT+T and enter the following

sudo apt install git

To install VS Code, download the .deb file. Locate the file and then install with

sudo apt install ./codefilename.deb

On MacOS

Install Homebrew, a popular package manager for MacOS among developers. Follow the install instructions.

To install VS Code, enter

brew install --cask visual-studio-code

To install Git, enter

brew install git

3. Creating a GitHub Account

Create an account on GitHub.

Configuring Git

git config --global user.name "John Doe"
git config --global user.email "johndoe@example.com"
git config --global init.defaultBranch main # The default branch used to be master
git config --global pull.rebase false # Sets default branch reconciliation; safer than rebasing

Check that the appropriate changes were made. 👇

git config --get user.name
git config --get user.email

MacOS: Configuring Git

echo .DS_Store >> ~/.gitignore_global
git config --global core.excludesfile ~/.gitignore_global

This tells Git to ignore .DS_Store files, which has to do with Finder.

Create an SSH Key

An SSH key is a secure identifier used to identify your machine.

ls ~/.ssh/id_ed25519.pub # Check if you have an Ed25519 algorithm key installed
ssh-keygen -t ed25519 # Create one if not

When prompted, the password is used to encrypt the private SSH key stored on your computer. Enter one if you want; not required.

Link Your SSH Key to GitHub

1. On GitHub, go to: Settings > SSH and GPG keys > New SSH Key
2. Name the key descriptive to your machine, something like thinkpad-xubuntu
3. Copy your public SSH key and paste it into the key field

   cat ~/.ssh/id_ed25519.pub
   

Test Your SSH Connection

1. Enter the following in the terminal

   ssh -T git@github.com
   

2. Verify that the fingerprint in the message matches GitHub’s public key fingerprint and enter yes

4. Using Git: Commit Messages (and Comments)

Git is a version control system (VCS).

A VCS tracks changes to code over time, allowing people to revert to an old version, create multiple branches, commit current edits, and push changes to the web for collaboration. It’s a really advanced save feature.

Think of Google Doc’s version history, but on steroids.

You can read more about version control systems on Pro Git.

Git vs. GitHub

Git is a program that works on your local machine.

GitHub is remote storage, where you can showcase your projects and collaborate with other developers.

The Git Workflow

^ From UW.

As you write code, you will want to periodically snapshot (or capture) your changes, which is accomplished with git add and git commit. These commits make up your version history. When you want to publish the changes, you will git push to GitHub. When you want to update your local repository, you will use git pull.

Creating and Updating Repositories

A repository (repo) is a location or “container” that stores a project’s code, commit (version) history, and files.

When you want to get a local copy of an online repository, you clone it to your local machine.

As mentioned, when you want to get the latest updates from the online repository, you pull them to your local machine. And when you make changes, you push them to the online repository.

Making Changes

1. Make changes
2. Stage changes
   • All of these files will share the same commit message
   • Use git add <filename or . to add all files in your current working directory>
3. Commit changes
   • Create a snapshot of your changes
   • Use git commit -m "Your commit message here"

Basic Git Syntax

program | action | options (optional) | destination

git commit -m "Message"
git add . # The option is omitted

Try: Create a Repo

1. On the GitHub homepage, create a new repository. Name it “test.”
2. To clone your repository to your local machine, copy what’s in the SSH option.
3. In your terminal, create a directory called repos and navigate into it with cd

   mkdir repos
   cd repos/
   

4. Now, you are in your repos directory. Clone your repo:

   git clone git@github.com:USERNAME/REPO-NAME.git
   

5. Navigate into your repo:

   cd test
   git remote -v # Checks the repo's connections
   

Try: Create a File (or Two)

1. Create a new file called helloworld.txt in your test repo with touch helloworld.txt.
2. Enter git status, which shows what files are being tracked.
3. Enter git add helloworld.txt. This adds your file to the staging area. Type git status again.
4. Enter git commit -m "Create helloworld.txt" and then git status.
5. Type git log to see your entry for the commit you just made.
6. Now create another file called README.md and write some text in it. Be sure to save the file and stage it. Make your commit message descriptive with git commit -m "Create README.md".
7. Type git push origin main to push the changes you’ve made locally to the remote repo.
8. Type git status.
9. Refresh your repo’s page on GitHub. What do you see?

Change the Git editor

If you type git commit without -m, you will write your commit message in Nano or Vim. To have it open in VS Code instead, enter this into your terminal:

git config --global core.editor "code --wait"

That being said, omitting the -m allows you to write a body for your commit message. Keep in mind that the subject line has a 72-character max on GitHub.

Tips for Writing Good Commit Messages

• Make atomic commits, which are commits that refer to only one feature or task
• Commit every time you make a meaningful change
• Use an active voice: “Fix grid layout”
• Keep your syntax consistent:
  • Capitalize the first letter in your subject line
  • Don’t end the subject line with a period
  • Wrap text at 72 characters
  • The body should explain the why for the commit, rather than how (as the code explains it)

See this article by cbeams for more.

Git Cheatsheet

git clone git@github.com:blah/blah.git
git push origin main
git pull

git add .
git commit -m "Commit message"

git status
git log

5. Parts of a Computer, Compilation, How to Create a Program

What’s Inside a Computer?

• Motherboard
• Processor (CPU)
• Random Access Memory (RAM)
• Storage (HDD, SSD, floppy, etc.)
• Graphics Processing Unit (GPU)
• Power Supply Unit (PSU)
• Fans, heat sink (for cooling)

^ From FHC Today.

Compilation Overview

^ From PrepBytes.

1. Source code (.cpp file)
2. Preprocessor/macro expansion
   • Processes the #include, #define, #ifdefs
   • Converts C++ code to C++ code
3. Compiler
   • Converts C++ to assembly (.s)
4. Assembler
   • Assembly to machine code/binary object files (.o)
5. Linker
   • Take object files and resolves external functions into executables
   • Gets libraries (.so, .dll, .dylib)
6. Executable (sent to CPU)

General Steps to Creating a Program

1. Define what the program does
2. Create a model of program - it may help to draw diagrams!
3. Write source code
4. Compile source code
5. Correct errors found during compilation
6. Create an executable and run program, using test data for input (try breaking your program)
7. Correct errors and validate the results of the program

Resources

• Git Cheat Sheet
• Setting Up Git
• Testing Your SSH Connection to GH