Unit 5: Software Engineering & Computing in Society

Purpose: Self-check on testing/debugging, version control, ethics, AI/ML, careers, history, and environmental impact. Instant feedback. Python 3.

Question 1 — Test design

A function divide(a, b) returns a/b. Which of the following is the BEST set of test cases?

divide(10,2), divide(8,4)
divide(10,2), divide(0,5), divide(10,0), divide(-6,2)
divide(2,10), divide(5,5)
divide("a", "b")

Solution:

(b) covers normal, boundary (0 numerator), edge (0 denominator), and negative cases. (a) and (c) test only happy paths.

Question 2 — Git basics

What does git commit do?

Sends your changes to a remote server
Records a snapshot of staged changes in your local repository
Permanently deletes your changes
Downloads someone else's changes

Solution:

git commit records staged changes locally. git push sends them to the remote.

Question 3 — Debugging

A program correctly handles 99% of inputs but crashes on the empty list. What kind of bug is this?

Syntax error
Logic error / boundary / edge case
Memory leak
Infinite loop

Solution:

This is an edge-case bug. Most testing checklists insist on testing empty/zero/null inputs because they often expose missed assumptions.

Question 4 — AI / Machine Learning

Which best describes supervised machine learning?

A program that thinks like a human
An algorithm that learns a function from labeled training examples (input, output) and then predicts outputs for new inputs
Software that always achieves 100% accuracy
A robot that walks autonomously

Solution:

Supervised ML learns a mapping from labeled examples. The model's accuracy is empirical, not guaranteed.

Question 5 — Ethics

A hiring algorithm is found to reject more applicants from one neighbourhood than another, even when qualifications are comparable. This is an example of:

A computer virus
Algorithmic bias
A memory leak
Open-source licensing

Solution:

Algorithmic bias — the system has internalized a pattern from biased training data or design choices, causing differential outcomes across groups.

Question 6 — History

Who is generally credited with writing the first algorithm intended for a machine (the Analytical Engine), in the 1840s?

Alan Turing
Ada Lovelace
Charles Babbage
Grace Hopper

Solution:

Ada Lovelace — her notes on Babbage's Analytical Engine include what is widely recognized as the first published algorithm.

Question 7 — Code review

Which is NOT a typical code-quality concern raised in a code review?

Magic numbers (unexplained literals)
Inconsistent indentation
Lack of comments on tricky logic
The colour of the editor's syntax highlighting

Solution:

Editor colour scheme is personal preference. (a), (b), (c) are real maintainability concerns.

Question 8 — Environmental impact

Roughly what fraction of global electricity demand is currently attributed to data centres (a typical figure used in the news as of the mid-2020s)?

About 0.01%
About 1-2%
About 50%
About 0% — they run on solar exclusively

Solution:

Estimates from the IEA put data-centre electricity at approximately 1-2% of global demand, growing rapidly with AI workloads. The exact figure is debated but the order of magnitude is robust.

Question 9 — Version control workflow

Which is the recommended workflow for working on a new feature in a team using Git?

Edit files directly on main, commit, push
Create a feature branch, commit there, open a pull request, merge after review
Email the changed files to teammates
Force-push to overwrite teammates' work

Solution:

Branch → commit → PR → review → merge is the standard collaborative workflow. Direct edits to main risk breaking shared work.

Question 10 — Software Development Life Cycle

In the SDLC, which phase comes IMMEDIATELY after design?

Requirements
Implementation
Maintenance
Retirement

Solution:

Typical SDLC: Requirements → Design → Implementation → Testing → Deployment → Maintenance.

Question 11 — Privacy

A free mobile game asks for permission to access your contacts and microphone, even though it is just a number-guessing game. The MOST appropriate response is:

Always grant — apps need this to function
Deny by default; only grant permissions clearly justified by the feature being used (least privilege)
Uninstall every app that requests any permission
Reset your phone

Solution:

The principle of least privilege — software should request only the permissions needed for the feature in use.

Question 12 — Career exploration

Which postsecondary path is BEST suited to someone interested in building large-scale software systems used by many users?

Bachelor of Computer Science / Software Engineering
Bachelor of Fine Arts (Visual Arts)
Bachelor of Linguistics (sole focus)
Diploma in Industrial Mechanics

Solution:

Computer Science or Software Engineering programs at any major Ontario university (Waterloo, U of T, McMaster, Western, Queens, etc.) are the most direct path. The other options are valuable but not focused on large-scale software development.