Principles of Software Construction Objects, Design, and Concurrency


Software engineers today are less likely to design data structures and algorithms from scratch and more likely to build systems from library and framework components. In this course, students engage with concepts related to the construction of software systems at scale, building on their understanding of the basic building blocks of data structures, algorithms, program structures, and computer structures. The course covers technical topics in four areas: (1) concepts of design for complex systems, (2) object oriented programming, (3) static and dynamic analysis for programs, and (4) concurrent and distributed software. Student assignments involve engagement with complex software such as distributed massively multi-player game systems and frameworks for graphical user interaction.

After completing this course, students will:

See a more detailed list of learning goals describing what we want students to know or be able to do by the end of the semester. We evaluate whether learning goals have been achieved through assignments and exams.


M/W 11:00 - 12:20 p.m. in POS A35

Jeremy Lacomis, TCS 362, office hours: see calendar Claire Le Goues, TCS 363, office hours: see calendar

Our TAs also provide an additional 15h of office hours each week; see details in the calendar.

The instructors have an open door policy: If the instructors' office doors are open and no-one else is meeting with us, we are happy to answer any course-related questions. Feel free to email us for appointments; we are also available over Zoom.

[course-calendar](## Course Calendar)


The schedule below reflects our current plans, but will be updated throughout the semester.

Date Topic Reading assignments*
Mon, Aug 26 Intro, IDEs, Build Systems, CI, Libraries
Wed, Aug 28 OO basics, Dynamic dispatch, Encapsulation
Fri, Aug 30 Lab 1 Course Infrastructure Setup
Mon, Sep 2 No Class, Labor Day
Wed, Sep 4 OO Analysis and UML
Fri, Sep 6 Lab 2 Encapsulation
Mon, Sep 9 HW 1 due Flash cards (Intro to OO and Libraries)
Mon, Sep 9 Responsibility Assignment
Wed, Sep 11 Inheritance and Delegation
Fri, Sep 13 Lab 3 Refactoring and Anti-patterns
Mon, Sep 16 HW 2 due Testing
Mon, Sep 16 Design Patterns
Wed, Sep 18 Design Patterns II
Fri, Sep 20 Lab 4 Design and UML
Mon, Sep 23 Midterm 1
Wed, Sep 25 Refactoring and Anti-Patterns
Fri, Sep 27 Lab 5 Inheritance and Delegation
Mon, Sep 30 HW 3a due Santorini: Intro to Design
Mon, Sep 30 Specifications and Unit Testing, Exceptions
Wed, Oct 2 Test Case Design
Fri, Oct 4 Lab 6 Unit Testing
Mon, Oct 7 HW 3b due Santorini: Design feedback
Mon, Oct 7 Refactoring for Testability
Wed, Oct 9 API Design
Fri, Oct 11 Lab 7 Test Doubles
Mon, Oct 14 No class, Fall Break
Wed, Oct 16 No class, Fall Break
Fri, Oct 18 No lab, Fall Break
Mon, Oct 21 HW 4 due Refactoring
Mon, Oct 21 Concurrency and Asynchrony in Typescript
Wed, Oct 23 Concurrency and Hazards
Fri, Oct 25 Lab 8 Concurrency & Promises
Mon, Oct 28 HW 3c due Santorini: Final design
Mon, Oct 28 Concurrency: Reactive Programming
Wed, Oct 30 TBD
Fri, Nov 1 Lab 9 ReactJS
Mon, Nov 4 HW 5 due Concurrency
Mon, Nov 4 TBD
Wed, Nov 6 Libraries and Frameworks
Fri, Nov 8 Lab 10 TBD
Mon, Nov 11 Midterm 2
Wed, Nov 13 Introduction to GUIs
Fri, Nov 15 Lab 11 Frameworks/Extensibility
Mon, Nov 18 HW 6a due Santorini: User Interface
Mon, Nov 18 Organizing Systems at Scale: Modules
Wed, Nov 20 TBD
Fri, Nov 22 Lab 12 TBD
Mon, Nov 25 TBD
Wed, Nov 27 No class, Thanksgiving Break
Fri, Nov 29 No lab, Thanksgiving Break
Mon, Dec 2 HW 6b due Santorini: God Cards
Mon, Dec 2 Static vs. Dynamic Typing, Static Analysis
Wed, Dec 4 DevOps
Fri, Dec 6 Lab 14 Design Pattern Review
TBD Final exam


Instructors: Jeremy Lacomis [jlacomis] and Claire Le Goues [clegoues]


Course Syllabus and Policies


Grading and Deadlines

Evaluation will be based on the following approximate percentages:

This course does not have a fixed letter grade policy; i.e., the final letter grades will not be A=90-100%, B=80-90%, etc.

Homework grading and regrading. We try to be transparent in our rubrics in our assignments. Feel free to ask instructors or TAs clarification questions about the rubrics before the assignment is due. If you disagree with a grade, please submit a regrade request within 7 days on Gradescope. Regrade requests need a justification, explaining why our assessment is inconsistent with the rubric. Regrade requests without such justification will be closed.

Each student can resubmit any one assignment milestone and it will be regraded as if it was the first submission (see below).

Participation and quizzes. You should expect a quiz at the start of nearly every lecture and often additional in-class activities within the lecture. When a reading assignment is given, the quiz will typically touch on the content from the reading material. Otherwise (and sometimes in addition), the quiz centers around the content from the most recent lecture or two. A quiz will typically have 1-2 questions and is graded pass/fail.

Labs. Labs will be graded on a pass/fail basis during recitations. You will have a chance during recitation to improve your solution. See a description here.

Late work. We understand that normal life events, including projects and exams in other courses and technical difficulties out of your control, can interfere with your ability to complete your work on time or attend lectures and recitations. Our philosophy is that our late work policy includes built-in flexibility but that the policy will be uniformly applied to all students in all circumstances. Exceptions to this policy will be made only with explicit accommodations, almost always involving a family or medical emergency with your academic advisor or the Dean of Student Affairs requesting the exception on your behalf.

Attendance and remote participation

This course, including recitations, is marked by the registrar as IPE ("delivered in-person, students are expected to be in the classroom during the course's scheduled meeting time"). We do not plan to make accommodations for remote attendance.

We strongly recommend attending lectures. We have regular in-class activities and quizzes that we expect you to complete in class. Attending recitations is required for grading labs.

In case of illness, quarantine, or other exceptional circumstances, we may be able to share recordings of lectures upon request on a case by case basis. Recordings may not be shared to protect the FERPA rights of all students in the classroom.


This course will occasionally assign mandatory readings, from the two text books below. The CMU library has both physical and electronic copies of these books. You can access all of these books for free electronically through the CMU library.

In addition, we list several optional readings that may be helpful with specific topics in the course. Especially if Java/Javascript is new to you, you might want to consider exploring additional books.

Time management

This is a 12-unit course, and it is our intention to manage it so that you spend close to 12 hours a week on the course, on average. In general, 4 hours/week will be spent in class, 1 hour on labs, and 7 hours on assignments. Please feel free to give the course staff feedback on how much time the course is taking for you.

Research to Improve the Course:

For this class, we are conducting research on teaching and learning. This research will involve some student work. You will not be asked to do anything above and beyond the normal learning activities and assignments that are part of this course. You are free not to participate in this research, and your participation will have no influence on your grade for this course or your academic career at CMU. If you do not wish to participate, please send an email to Chad Hershock ( Participants will not receive any compensation. The data collected as part of this research will include student grades. All analyses of data from participants’ coursework will be conducted after the course is over and final grades are submitted. The Eberly Center may provide support on this research project regarding data analysis and interpretation. The Eberly Center for Teaching Excellence & Educational Innovation is located on the CMU-Pittsburgh Campus and its mission is to support the professional development of all CMU instructors regarding teaching and learning. To minimize the risk of breach of confidentiality, the Eberly Center will never have access to data from this course containing your personal identifiers. All data will be analyzed in de-identified form and presented in the aggregate, without any personal identifiers. If you have questions pertaining to your rights as a research participant, or to report concerns to this study, please contact Chad Hershock (

Collaboration policy and academic integrity

The usual policies apply, especially the University Policy on Academic Integrity. We expect that your work on assignments, projects, and exams will be your own work. The key guiding principle of academic honesty in this course is: "You may not copy any part of a solution to a problem that was written by another student (in this or prior iterations of the class), or was developed together with another student, or was delegated to another person. You may not look at another student's solution, even if you have completed your own, nor may you knowingly give your solution to another student or leave your solution where another student can see it." Note that this implies that you cannot publicly post your solutions on GitHub (e.g., as part of a portfolio during job applications). We also expect and respect honesty when communicating with the course staff.

Any violation of this policy is cheating. We use automated systems to detect software plagiarism. These automated systems are highly effective and, so far, have detected software plagiarism almost every semester. The minimum penalty for cheating will be a zero grade for the whole assignment. Cheating incidents will also be reported through University channels, with possible additional disciplinary action (see the University Policy on Academic Integrity).

For labs and homeworks you are allowed to use various tools and help available to professional programmers, such as online documentation, online tutorials and support forums like Stackoverflow, and AI assistants like Copilot and ChatGPT. You are allowed to post technical questions about aspects of the homework elsewhere, as long as you do not ask other humans to complete the work for you. Whenever you use external resources like this, you are still fully responsible for the correctness of your solution and complying with licenses. Note that content generation tools often create plausible-looking but incorrect answers, which will not receive credit.

When you use AI assistants in homework, some assignments may require you to briefly describe their use and your experience with the homework submission.

Here are some examples of behavior that are inappropriate:

Here are some examples of acceptable behaviors:

There is no statute of limitations for violations of the collaboration policy; penalties may be assessed (and referred to the university disciplinary board) after you have completed the course, and some requirements of the collaboration policy (such as restrictions on you posting your solutions) extend beyond your completion of the course.

If you have any question about how this policy applies in a particular situation, ask the instructors or TAs for clarification.

Audit Policy

If you desire to audit the course, our general requirement is that you complete homeworks to achieve at least 50% of the total homework grade. Solutions do not need to be fully complete, but we encourage you to attempt to do so. We additionally encourage you to attend lectures and complete labs, but you are not required to do so. You should not attend our midterm exams or final exam.

Your health matters

When we say "your health matters" we mean exactly that: Your health matters. We don't intend to imply that other peoples' health does not matter, or that your health matters more or less than theirs. We know that CMU can be a stressful, risky environment, and your health is the health that is relevant in this conversation. Worries about Covid-19 and possible remote classes do not help.

Please take care of yourself. Do your best to maintain a healthy lifestyle this semester by eating well, exercising, avoiding drugs and alcohol, getting enough sleep and taking some time to relax. This will help you achieve your goals and cope with stress.

All of us benefit from support during times of struggle. You are not alone. There are many helpful resources available on campus and an important part of the college experience is learning how to ask for help. Asking for support sooner rather than later is often helpful.

If you or anyone you know experiences any academic stress, difficult life events, or feelings like anxiety or depression, we strongly encourage you to seek support. Counseling and Psychological Services (CaPS) is here to help: call 412-268-2922 and visit their website at Consider reaching out to a friend, faculty or family member you trust for help getting connected to the support that can help.

If you are worried about affording food or feeling insecure about food, there are resources on campus who can help. Email the CMU Food Pantry Coordinator to schedule an appointment:

Respect for diversity. It is our intent that students from all diverse backgrounds and perspectives be well served by this course, that students’ learning needs be addressed both in and out of class, and that the diversity that students bring to this class be viewed as a resource, strength and benefit. It is my intent to present materials and activities that are respectful of diversity: gender, sexuality, disability, age, socioeconomic status, ethnicity, race, and culture. Your suggestions are encouraged and appreciated. Please let us know ways to improve the effectiveness of the course for you personally or for other students or student groups.

Accommodations for students with disabilities. If you have a disability and have an accommodations letter from the Disability Resources office, we encourage you to discuss your accommodations and needs with us as early in the semester as possible. We will work with you to ensure that accommodations are provided as appropriate. If you suspect that you may have a disability and would benefit from accommodations but are not yet registered with the Office of Disability Resources, we encourage you to contact them at

Informal feedback on this course

We are planning many changes to this course in this semester and not everything will work out smoothly the first time. We’d like you to provide ongoing feedback on your experience in the course, so that we can take into account your experience and adapt our practices to make the course work for you.

Outside of the regular course meetings and Piazza, you can submit feedback about anything in the course per email to the instructors or ask TAs to forward them anonymously. We will read every message submitted and use your feedback to try to improve the way we are teaching.