Eboard 01: Getting started

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Approximate overview

• Preliminaries
  • Notes and news
  • Upcoming work
  • Extra credit
  • Questions
• Course goals
• Course structure
• ADTs and data structures
• A quick intro to object-oriented design
• Designing a stack ADT (an exercise)

Preliminaries

• Consider grabbing a mask.
  • Even before covid, post winter break was full of illnesses.
  • The graphs I’ve seen suggest that covid incidence is rising.
• Sit where you’d like, within reason.
• If you don’t know the people next to you, please introduce yourselves.

News / Etc.

• Welcome to CSC207!
• I’m Sam (or SamR)
• Our class mentor is Elene Sturua
• We’ll be using two “books” for this course: The readings I write (or wrote) and CLRS.
• I type class notes in markdown and post to the Web site.
  • It’s like magic (I hope).
• You will find that I call on students randomly using a set of cards with your names on them.
  • I use this process to give you practice “thinking on your feet”, as it were.
  • I also use this process to help everyone realize that they are not the only one who is puzzled.
  • And I use the process to push you a bit.
  • Feel free to say “I’m not sure” or “I’d prefer not to answer.”
  • If you don’t want to be called on in class, please let me know.
• We are a community. Treat each other with respect. If you (think you) know more than your partner, support, don’t overwhelm.
• Sam has some personal issues. There may be some hiccups in the class.

Upcoming work

• Readings due Tuesday night
  • An introduction to Java
  • Simple Java for C progammers
  • Arrays in Java
  • Submit double dagger problems at https://www.gradescope.com/courses/690101/assignments/3974734/
• Also due Tuesday night
  • Introductory survey
  • Syllabus review

Tokens

I don’t know what your prior experience with tokens is. I give them for academic/scholarly events, cultural events, peer events, wellness events, and a few other things. Only those I record in the daily eboards are available. Please log them within three days.

Academic/Scholarly

• Friday, 2024-01-26, 6:00–7:30 p.m., JRC 101. Celebration of MLK day with Alan Page.

Cultural

• Saturday, 2024-01-27, 11:55 a.m.–3:55 p.m., Harris Cinema. Met Opera presents Carmen.

Peer

• Saturday, 2024-01-27, 10:00 a.m.–1:00 p.m., Field House. Grinnell Track and Field Invitational.

Wellness

Misc

Other good things

Attendance

• Since it’s the first day of class, I will take attendance.
  • It will take me at least a few weeks to learn all of your names.
  • _Please say your name before you ask or answer questions.
• Today’s attendance protocol. When I say your name, answer as follows.
  • “Hi, my name is FORENAME SURNAME.”
  • Optional: “My pronouns are ….”
  • “You can call me PRIMARY_NAME.”
  • “If you must address me by surname, you can call me Mr./Ms./Mx./Sr./Srta./etc. SURNAME [San].”
  • “This semester, I’m looking forward to ….”
  • Optional: A question

Excited about

• This class (learning Java) [x2].
• Sucking up to faculty.
• Only one STEM class.
• New skills.
• Schedule. (Only one non-STEM class.)
• Three classes.
• No 8am classes. [x4]
• More classes in major.
• Grading.
• Not grading.
• Not having classes on weekends.
• Things settling down.
• Time with friends.
• Springtime in four months.
• CS Classes
• Tennis [x2]
• Moving forward in the CS major.
• Taking CS a non-CS major.
• Know exams. [x2]

Questions

• What’s the work in the class?
  • Weekly mini-projects (some individual, some group). Goal of 3-5 hours.
    • EMRI
    • First redo is free (for MR).
    • Subsequent redos cost tokens.
    • When Sam is organized, there will be a clear rubric.
  • Portfolio learning assessments (for the most part)
    • E.g., Learning Objective: Parse Input
    • Submit: Code you’ve written + a bit of explanation.
    • All online, arbitrary amounts of time (well, a week)
  • A few LAs will involve a direct question.
  • Free redos on all LAs (as many as you need).
  • Sam will release LAs every week or two, if all goes well.
• How should we contact you.
  • Preference: Teams
  • Alternate: Email. Send a reminder if I don’t respond within a day.
  • Emergency: Text. 641-990-2947.
  • Serious emergency: Call.
• How frequent is the group work?
  • Labs (almost) every class.
  • Probably 3/12 mini-projects.
• How do tokens work?
  • I charge them automatically.
  • You apply for new tokens on a not-yet-available Gradescope problem set.
• What’s a SoLA?
  • Cruft from an old version of the course. “Set of learning assessments.”
• Do we have to turn in every individual lab?
  • TBD.
  • Likely the “Sam says stop here” model.
  • Even if I don’t require you to turn in everything, you should still reflect on the remainder (or actually do the remainder).
• What’s the rhythm of the course?
  • Mini-projects released every Wednesday, due every Tuesday at 11pm.
  • LAs released approximately weekly starting in week two. Released on Friday, due the following Friday (probably late).
• Are groups for assignments assigned or self selected?
  • Class/lab: Random
  • Mini-projects: Both
• What’s the late work policy?
  • 1 token for up to two days. Applies to readings, labs, metacognitive reflections, mini-projects. (Not LAs; no late LAs.)
• What will class time look like?
  • Varies.
  • Basic model one: Sam answers accumulated reading questions then you work on lab in randomly assigned pairs while we wander around and ask you questions. (And answer your questions.)
  • Basic model two: Sam answers accumulated reading questions then ask you some design questions which we do in a Think-Pair-Share (TPS) model.
  • Basic model three: Same first part; something like a tech interview.
• When are your office hours?
  • Still TBD
  • Feel free to TM me to set up a time.
• Are there exams?
  • No. The LAs serve as the exam equivalent.
• What are metacognitive reflections?
  • Required opportuities to reflect on your learning.
  • See the page in handouts.
• Will we be expected to use Javadoc?
  • Of course.
• Will we be expected to follow standard style guidelines for writing Java code or can we write random crap like we’ve done in the past?
  • Google Java style guidelines
  • Those specify an indentation of two spaces.
  • Our IDE helps automatically reformat.
• How much of CLRS will we cover?
  • Not a lot.

Course goals

• Teach you to be “real” computer scientists.
• Design and implement algorithms.
• Analyze algorithms.
• Design and implement and analyze data structures.
• Build non-trivial program.

For building non-trivial programs

• Use OOD
• Use some standard tools (IDEs, (potentially) build tools, version control systems)

Course structure

See above.

ADTs and data structures

• Ways of organizing collections of data.
• ADT (abstract data type): Overall philosophy/methods (the interface)
• Data structure: Underlying implementation (organize data in memory and the effects of doing so)

Don’t forget to ask me when I use a TLA that you don’t understand.

Designing a stack ADT (an exercise)

We will use the Think-Pair-Share (TPS) approach.

ADT: Use the PUM method for ADTs.

• P: Philosophy (organizing principle)
• U: Uses (or use cases)
• M: Methods

The philosophy of stacks

• Stacks are collections of data in which you can add and remove data. You add and remove data only at the “top” of the stack.
• Stacks follow a last-in, first-out policy; the thing you remove is the most-recently-added of the things still on the stack.

Some uses (we could use stacks for …)

• To-do list: Or maybe not. The first thing you add will be the last thing you do (and you may never get it done).
• (Helps with building one-to-one functions.)
• The back button on a standard browser usually keeps track of a stack of the things you’ve seen.
• Most programming languages have a “call stack”, where they put the context of a procedure on a stack of procedure contexts. This is particularly useful for recursive procedures.
• Simulating the stack of plates in the dining hall.

Core methods:

• ??? push(???) - add an element
  • C: void push(string_stack *s, char *str)
  • Requires not full.
• ??? pop(???) - remove and return an element
  • C: char *pop(string_stack *s); (Requires not empty)
• char *peek(string_stack *s); - look at the top value, but don’t remove it. (Requires not empty)
• boolean isEmpty(string_stack *s);
• boolean isFull(string_stack *s);

Optional methods:

• void popmany(string_stack *s, int num_to_pop);
  • Who needs for loops? We just want to throw stuff away without looking at it.
  • perhaps char ** popmany(string_stack *s, int num_to_pop);
• int size(string_stack *s);