All the course activities are scheduled to be in-person activities this semester.

Apdx B: Course PoliciesApdx D: Getting Help


Apdx C: FAQ

FAQs on: General

FAQ Where is everything?

The Weekly Schedule Page presents all you need to know in chronological order (for each week) while the other pages have some of the same content organized by topic.

The Weekly Schedule Page is the one page you need to refer weekly. Although there is a lot of content in the Admin Info page and the Textbook page -- which you are welcome to read in those respective pages -- the same content is also cross-embedded in the corresponding weekly schedule pages. Such cross-embedded extracts usually appear in expandable panels and can be identified by the symbol in the panel title.


FAQ What are the extra requirements to get an A+?

In CS2113, A+ is not given simply based on the final score. To get an A+ you should,

  • score enough to be close to the higher end of the A grade band.
  • be considered technically competent by peers and tutor (based on peer evaluations and tutor observations).
  • be considered helpful by peers (based on peer evaluations and tutor observations).
  • In particular, you are encouraged to be active on the forum and give your inputs to ongoing discussions so that other students can benefit from your relatively higher expertise that makes you deserve an A+.
  • Whenever you can, go out of your way to review pull requests created by other team members.

FAQ Why so much bean counting?

Sometimes, small things matter in big ways. e.g., all other things being equal, a job may be offered to the candidate who has the neater looking CV although both have the same qualifications. This may be unfair, but that's how the world works. Students forget this harsh reality when they are in the protected environment of the school and tend to get sloppy with their work habits. That is why we reward all positive behavior, even small ones (e.g., following precise submission instructions, arriving on time etc.).

But unlike the real world, we are forgiving. That is why you can still earn full marks for participation even if you miss a few things here and there.


FAQ Why use a separate website instead of Canvas?

We have a separate website because some of the course information does not fit into the structure imposed by Canvas.


FAQ Why very narrow project scope?

Defining your own unique project is more fun.

But, wider scope → more diverse projects → harder for us to go deep into your project. The collective know-how we (i.e., students and the teaching team) have built up about SE issues related to the project become shallow and stretched too thinly. It also affects fairness of grading.

That is why a strictly-defined project is more suitable for a first course in SE that focuses on nuts-and-bolts of SE. After learning those fundamentals, in higher level project courses you can focus more on the creative side of software projects without being dragged down by nuts-and-bolts SE issues (because you already know how to deal with them). However, we would like to allow some room for creativity too. That is why we let you build products that are slight variations of a given theme.

Also note: The freedom to do 'anything' is not a necessary condition for creativity. Do not mistake being different for being creative. In fact, the more constrained you are, the more you need creativity to stand out.


FAQ Why can't I use my favorite tool/framework/language etc.?

We have chosen a basic set of tools after considering ease of learning, availability, typical-ness, popularity, migration path to other tools, etc. There are many reasons for limiting your choices:

Pedagogical reasons:

  • Sometimes 'good enough', not necessarily the best, tools are a better fit for beginners: Most bleeding edge, most specialized, or most sophisticated tools are not suitable for a beginner course. After mastering our toolset, you will find it easy to upgrade to such high-end tools by yourself. We do expect you to eventually (after this course) migrate to better tools and, having learned more than one tool, to attain a more general understanding about a family of tools.
  • We want you to learn to thrive under given conditions: As a professional Software Engineer, you must learn to be productive in any given tool environment, rather than insist on using your preferred tools. It is usually in small companies doing less important work that you get to chose your own toolset. Bigger companies working on mature products often impose some choices on developers, such as the project management tool, code repository, IDE, language etc. For example, Google used SVN as their revision control software until very recently, long after SVN fell out of popularity among developers. Sometimes this is due to cost reasons (tool licensing cost), and sometimes due to legacy reasons (because the tool is already entrenched in their codebase). While programming in school is often a solo sport, programming in the industry is a team sport. As we are training you to become professional software engineers, it is important to get over the psychological hurdle of needing to satisfy individual preferences and get used to making the best of a given environment.

Practical reasons:

  • Some of the topics are tightly coupled to tools. Allowing more tools means tutors need to learn more tools, which increases their workload.
  • We provide learning resources for tools. e.g. 'Git guides'. Allowing more tools means we need to produce more resources.
  • When all students use the same tool, the collective expertise of the tool is more, increasing the opportunities for you to learn from each others.

Meanwhile, feel free to share with peers your experience of using other tools.


FAQ Why so many small submissions?

The high number of submissions is not meant to increase workload but to spread it across the semester. Learning theory and applying them should be done in parallel to maximize the learning effect. That can happen only if we spread theory and 'application of theory' (i.e., project work) evenly across the semester.

In addition, spreading the work across the semester aligns with the technique that we apply in this course to increase your retention of concepts learned.


FAQ Why not move to a newer Java version (e.g., 21)?

While we are aware that Java 21 is a more recent LTS version of Java, we are sticking with Java 17 for the time being. We plan to move to Java 21 in a future semester when its adoption is sufficiently high.


FAQ When can we see the quiz answers?

In most quizzes, answers will be released within a day after the quiz deadline.

On a related note, if you are not confident about the answer you've selected for a question, you are welcome to discuss it in the forum, even if the submission deadline is not over yet (but one question per thread please).


FAQs on: iP

FAQ How are the iP git tags used in grading?

Adding a git tag in the iP is a self-declaration that you think you are done with the iP increment. We take your word for it. We don't check the code to see if you have actually done the said increment. Therefore, it is just a mechanism for you to self-declare progress and for us to monitor those progress declarations.


FAQ What if I discovered a bug after I finished an increment?

Go ahead and fix it in a subsequent commit. There is no need to update the previous commit or move the corresponding tag to the new commit. As we do not test your code at every tag, earlier bugs will not affect your grade as long as they are fixed eventually. Similarly, feel free to improve the code of previous increments later.


FAQ I did multiple increments in the same commit. How to fix?

You can add the corresponding tags to the same commit.
Optionally, if you haven't pushed the commit to the fork yet, you can try to figure out how to split that commit into multiple commits.


FAQ The requirements of an increment scheduled for this week is already satisfied by the work I did in an earlier week. What now?

You can add the corresponding tag to the earlier commit (or the latest commit -- it doesn't matter) and push the tag.


FAQ My iP increments are not detected by the dashboard because I forgot to push my tags earlier. What now?

Not to worry. Just push the tags now. They will be detected by the dashboard at the next update. There is no penalty if mistakes are detected and fixed soon after.


FAQ Oh no! I made a mistake in my tag/branch name.

It's OK; correct it now.


FAQ What if I did the increment in the master branch, not in branch-___ as required?

It's fine. Be more careful in the future. Your iP marks will not be affected for missing an occasional deliverable such as this one.

If you still want to make that branch-___ item green in the iP dashboard, you can simply create a branch with the required branch name, do some commits in it, and merge it to master. The dashboard will accept it as long as it has the right name and merged to the master branch.


FAQ Can I use other data formats (e.g., serialized objects) to save tasks?

Yes, provided it doesn't require the user to install another software.
Also note that in the team project, there is a project constraint that requires the data to be saved in a human editable format.


FAQs on: Tutorials

FAQ What kind of questions can I ask the tutor?

TLDR: In this course, tutor's main job is to deliver tutorials. Hence, tutors can answer questions related to (and arising from) the tutorial delivery. But they are not allowed to answer admin questions. They are not allowed to help with technical issues.

  • Good I did not understand your explanation of that question. Why did you say "a b c"?
    Reason: This question is a follow-up from a tutorial discussion.
  • Good This is how I understood coupling. Is that correct?
    Reason: This question shows you have put in some effort to learn the topic and seeking further clarification from the tutor.
  • Bad What is coupling? | What is SLAP?
    Reason: These are concept covered in the textbook and other resources provided.

FAQ What if I can't attend a tutorial due to a valid reason (e.g., MC)?

See the following course policy:


FAQ What if I can't attend a tutorial due to another commitment (e.g., interview)?

Our tutorial participation bar has enough of a buffer to allow an occasional absence (irrespective of the reason for absence). While we are not able to make special arrangements for absences due to reasons not accepted as valid by NUS (e.g., due to family event, interview, travel delays, overslept etc.), such absences are unlikely to affect your participation marks unless frequent.

  • You are welcome to keep your tutor informed of such absences as a courtesy, but it is not a requirement.
  • If you miss a tutorial, do try to catch up as best as you can .

FAQ Can the tutorial be made longer (e.g., 2 hours)?

In the past, many students have requested to increase the tutorial duration because a mere hour is barely enough to get through all the tutorial tasks. Increasing the tutorial time is not possible due to lack of venues and tutors. Instead, let's try to make the best of the one hour available by coming well-prepared and starting on time. Note that the better prepared you are, the higher the chance of completing all activities allocated to a tutorial within time.


FAQs on: tP

FAQ Why the need to narrow down the user profile?

  • It is an opportunity to exercise your product design skills because optimizing the product to a very specific target user requires good product design skills.
  • It minimizes the overlap between features of different teams which can cause plagiarism issues. Furthermore, higher the number of other teams having the same features, less impressive your work becomes especially if others have done a better job of implementing that feature.

FAQ How narrow can we make the target market?

The size of the target market is not a grading criterion. You can make it as narrow as you want. Even a single user target market is fine as long as you can define that single user in a way others can understand (reason: project evaluators need to evaluate the project from the point of view of the target users).


FAQ Can we change the target user and value proposition later in the project?

Yes. If the submission deadline is not over yet, use the same link to update the submission. If the submission deadline is over, email the updated name, target user, value proposition to cs2113@comp.nus.edu.sg.


FAQ What if the chosen user stories for MVP is not enough to do a meaningful work division among team members?

In that case, at a later stage, you can add more user stories until there is enough for a meaningful work distribution. But at this point focus on selecting the smallest sub-set of must_have user stories only.


FAQ How many features should we put in the MVP?

Aim for the smallest set of features the product cannot do without. Even a most basic version of those features is enough. After completing that feature set, you can add more if there is time left.


FAQ What's the deadline for tP iterations?

The deadline for tP iterations is the Thursday 23:59 in the week it is due, unless a different date is specified in the instructions of that iteration.


FAQ What if we overshoot the deadline for a tP iteration?

It is OK (i.e., no penalty) if you overshoot the deadline in initial iterations. Adjust subsequent iterations so that you can meet the deadline consistently (which is an important learning outcome of the tP) by the time you reach the end of the tP.


FAQ Who should create issues?

We recommend that (when possible) the person allocated to perform the task should also create (and manage) the issue. This will help everyone practice this aspect of the project, and spread the workload among team members.


FAQ Can we use issues to track non-coding tasks? e.g., a submission

Yes (an example), although having too many non-coding tasks in the issue tracker can make it cluttered.


FAQ How do we track 'sub-task' relationships between tasks?

GitHub Issues does not have a direct way of doing this. However, you can use a task list in the issue description to indicate sub-tasks and corresponding issues/PRs -- (an example)


FAQ Is it OK to assign multiple members to the same task?

This is discouraged in the tP, as it makes task allocations (and accountability) harder to track.
Instead, shared tasks can be split into separate issues. For example, instead of creating an issue Update teams page with own info and assigning it to all team members (in which case, this issue can't be closed until all members do their part), you can create issues such as Update teams page with John's info that can be assigned to individual members.


FAQ When all members are updating the same document, can we create one issue and assign it to all?

A: In the tP (in which our grading scripts track issues assigned to each member), it is better to create separate issues so that each person's work can be tracked separately. For example, suppose everyone is expected to update the User Guide (UG). You can create separate issues based on which part of the UG will be updated by which person e.g., List-related UG updates (assigned to John), Delete-related UG updates (assigned to Alice), and so on.


FAQ Must there be a corresponding issue for each PR?

This is encouraged, while not a strict rule. Creating an issue indicates 'a task to be done', while a PR is 'a task being done'. These are not the same, and there can be a significant time gap between the two.
Furthermore, posting an issue in advance allows the team to,

  • anticipate a PR is coming
  • discuss more about the task (in the issue thread) e.g., alternatives, priority
  • indicate who will be doing the task (by adding an assignee), when it should be done (by adding it to a milestone)

FAQ Who should merge PRs? e.g., PR author, reviewer, team lead?

It is up to the team to decide. However, we discourage unilateral PR merging i.e., you create and merge PRs without any reviews/oversight from others, unless the PR is trivial changes.


FAQ Why not allow user to input the command one field at a time?

While this multistep-command approach (i.e., giving the user a series of prompts to enter various data elements required to perform an action) has its benefits (e.g., no need to memorize the command format), a deeper look reveals why the one-shot-command approach is better.

Before delving any further, note how leading CLI-centric software such as Git and Linux don't use the multistep approach either. Why?

The multistep approach basically results in a 'text-based GUI simulation' that is harder to use than an actual GUI (obviously), whereas a well-designed CLI in an expert's hands can perform tasks faster than an equivalent GUI (which is what we are going for). A person good at typing and remembers the command can type a command faster than a user going through a type-read-type-read sequence required by the multistep-command. Now imagine user made a mistake in the response to an earlier prompt -- correcting that would take a lot more work.

That being said, multistep commands can complement the one-shot-command approach in specific cases e.g.,

  • as a crutch for new users to learn the command format
  • to be used for rarely-used tasks or tasks requiring multiple steps (e.g., importing data from a file)

FAQ How detailed the DG should be? Do we have to describe every feature/component?

The DG is primarily meant to help current/future developers. In general, the DG is expected to provide minimal yet sufficient guidance for developers, serving them in the following ways:

  • It act as a starting point for developers, before they can dive into the code itself e.g., by providing an architecture-level overview of the system
  • It provides a roadmap to developers e.g., pointing out where important information can be found in the code
  • It complements the code, providing info/perspectives not specified in the code (e.g., rationale for high-level design choices, details of dev ops)
    or not easy to grasp from the code (e.g., architecture level view, visual models).

Therefore, decide based on how the inclusion/exclusion affects that target audience (you belong to the target audience too!) in achieving the above objectives.


FAQ Can UML diagrams be used in project submissions?

Not a good idea. Given below are three reasons each of which can be reported by evaluators as 'bugs' in your diagrams, costing you marks:

  • They often don't follow the standard UML notation (e.g., they add extra icons).
  • They tend to include every little detail whereas we want to limit UML diagrams to important details only, to improve readability.
  • Diagrams reverse-engineered by an IDE might not represent the actual design as some design concepts cannot be deterministically identified from the code e.g., differentiating between multiplicities 0..1 vs 1, composition vs aggregation.

FAQ How much code/features is enough to get full marks?

Not surprisingly, a common question tutors receive is "can you look at our project and tell us if we have done enough to get full marks?". Here's the answer to that question:

The tP effort is graded primarily based on peer judgements (tutor judgements are used too). That means you will be judging the effort of another team later, which also means you should be able to make a similar judgement for your own project now. While we understand effort estimating is hard for software projects, it is an essential SE skill, and we must practice it when we can.

The expected minimum bar to get full marks for effort is given here.

If you surpass the above bars (in your own estimation), you should be in a good position to receive full marks for the effort. But keep in mind that there are many other components in the tP grading, not just the effort.


FAQ Is LoC graded in the tP?

LoC is not graded. But if there is a significant mismatch between the LoC numbers and the 'effort' rating a student received, we take a closer look at the case to find out the reason for the mismatch, and revise marks if necessary.


FAQ Is it OK if different members modified different components?

No, we advise against that. Instead, divide the work based on features/enhancements instead of components. But you should still allocate different members to be 'in charge of' different components.


FAQ Must we fix all bugs reported and all enhancements suggested by testers?

Not necessarily. Choose based on importance.

In any project, there are always things that can be done 'if there was more time'. If fixing a certain bug has low impact on users, and fixing it is not as important as the work done (or intend to do in the current iteration), you can justify not fixing it with the reason 'not in scope' of the current iteration.

Similarly, a missing feature enhancement can be justified as 'not in scope' if implementing that could have taken resources away from other important project tasks.

Bugs and possible enhancements 'not in scope' will not be penalized.


FAQ Why not wait till the end to add/update the DG diagrams?

Here are some reasons:

  • We want you to take at least two passes at documenting the project so that you can learn how to evolve the documentation along with the code (which requires additional considerations, when compared to documenting the project only once).
  • It is better to get used to the documentation tool chain early, to avoid unexpected problems near the final submission deadline.
  • It allows receiving early self/peer/instructor feedback.

FAQ What if someone took over a feature from another team member?

In terms of effort distribution, it's up to the team to tell us who did how much. Same goes for assigning bugs. So, it's fine for someone to take over a feature if the team is able to estimate the effort of each member, and they have a consensus on who will be responsible for bugs in that feature.
For code authorship, only one person can claim authorship of a line, and that person will be graded for the code quality of that line. By default, that will be the last person who edited it (as per Git data) but you can override that behavior using @@author tags.


FAQs on: tP PE

FAQ What time does the PE end?

If you need to, you should be able to leave the PE after 5.45pm, as the part III of the PE (i.e., the last task to be done during the PE slot) can be done later (but you should before the midnight of the same day).


FAQ Can I (i.e., the tester) add more information about the bug when I object to a dev team's response?

Yes, you may. Given that the dev team did not get to see this addition info when they triaged the bug, the weight such additional info add to your case is lower than if you had that info in the initial bug report. Nevertheless, it can still help your cause, especially if the dev team should have thought about that info on their own, even if they were missing in the initial bug report.


FAQ What if the team rejected my bug report without giving a reason?

You can disagree with the rejection, and the teaching team will likely rule in your favor in the next phase.


FAQ If the bug I reported is NotInScope, how does it affect my accuracy bonus?

A bug that is type.Accepted or type.NotInScope can boost your accuracy if the severity.* you chose matches the eventual severity.* of the bug. Same for type.* (the type.* will not be considered for accuracy).


FAQ If a bug is NotInScope, does the severity.* label still matter?

Yes. A higher severity means the enhancement you suggested is of higher value/importance; you earn more credit for doing so.


FAQs on: tP Troubleshooting

FAQ PR passed CI before merging, but fails CI after merging. How come?

It is possible that the master branch has received new commits after your PR passed CI the last time. So, if GitHub indicates that your PR is not up-to-date with the latest master branch, synchronize your PR branch with the master branch (which will run the CI again) before merging it.


FAQ All tests pass locally, but the same code fails CI in the PR. How come?

First, check which OS it is failing in. Some behaviors can be OS-dependent. For example, file paths are case-insensitive in Windows but not in Unix/Mac.

Second, note that PR CI does a temporary merge of master branch to the PR branch before running tests, to verify if the checks will pass after you merge this PR. So, if the master branch has progressed after you started your PR branch, those new commits can affect the CI result. The remedy is to pull the master branch to your repo, merge it to your PR branch, and run tests again (which should fail as well, but you can now find the reason for the failure and fix it).


FAQ Some students will be testing less/more buggy products than others? Isn't that unfair?

As each product is tested by 4-5 testers, after all PE bugs have been finalized, we know how 'buggy' each product is. We then use that information for calculating your PE-related marks. So, the marks are calibrated to match the bugginess of the product you tested.


FAQ What if the product I tested has hardly any bugs?

If the total bugs found (by all testers) in a product is below a certain level, we compensate those testers by increasing the weightage given to PE-D performance, and their dev-testing results.


FAQ What if the product I tested is very buggy? Am I expected to find all those bugs?

No. Given the PE has only a short time, we don't expect you to find all bugs in the product. To get full marks, you only need to report a certain percentage of the bugs (e.g., half), or a certain quantity of bugs (the quantity also factors in the nature of the bug e.g., severity), whichever is lower.


FAQ Do we need to justify even if we accept the bug as is?

No need to provide a justification if you accept the bug without any changes to it.


FAQ So, those who write more code will be hit with more bugs? How's that fair?

Penalty for bugs is applied based on bug density, not bug count. Here's an example:

  • n bugs found in Ann's feature; it is a big feature consisting of a lot of code → marks for dev testing: 4
  • n bugs found in Jim's feature; it is a small feature with a small amount of code → marks for dev testing: 1

Although both had the same number of bugs, as Ann's work has a lower bug density than Jim's, she earns more marks for the dev testing aspect.


FAQ What if the bug is real but the tester used the wrong label (e.g., used the wrong type.*). Can we reject that bug?

A bug is a bug irrespective of the label used. Instead of rejecting, rectify the label.


FAQ What if the bug the tester reported is legit but the expected behavior tester suggested is not correct?

You should accept the bug but state that you disagree with the expected/suggested behavior. Reason: the main job of the tester is to detect bugs; suggesting a solution is optional.


FAQ Can I (i.e., the tester) add more information about the bug when I object to a dev team's response?

Yes, you may. Given that the dev team did not get to see this addition info when they triaged the bug, the weight such additional info add to your case is lower than if you had that info in the initial bug report. Nevertheless, it can still help your cause, especially if the dev team should have thought about that info on their own, even if they were missing in the initial bug report.


FAQ What if the team rejected my bug report without giving a reason?

You can disagree with the rejection, and the teaching team will likely rule in your favor in the next phase.


FAQs on: Exam

FAQ Can we have more past year papers and model answers?

You are welcome to try past exam papers available in the library and post answers in the forum to discuss with others. The teaching team will contribute to those discussions as well, and ensure you reach a reasonable answer.

Caution: The scope of the course and the exam format evolve over time and some past questions may not be exactly in sync with the current semester.



Apdx B: Course PoliciesApdx D: Getting Help