CSC 207.01 2019S, Class 25: Pause for breath
Overview
- Preliminaries
- Notes and news
- Upcoming work
- Extra credit
- Friday PSA
- Questions
- Sorted linked priority queues (continued)
- Array-based queues
- More testing
Preliminaries
News / Etc.
- Sit where you’d like.
- Donuts!
- If you would like my notes on the things that I do not put on the
eboard and promise not to distribute them to others, I can send them
to you. (I need an email from you indicating that you promise not
to distribute them to others.)
- Welcome to John Gouwar, our new class mentor.
Upcoming work
- Readings for Monday: Lots!
- Makeup exam 1 due Thursday the 11th
- Required prologue due TONIGHT!
- I will report back on exam times on Saturday morning
- I will also distribute unit tests on Saturday morning
- Isabelle Demers concert, Saturday at 3:00 p.m. in Herrick
- Singers concert, April 7 at 2pm
- 30 Minutes of Mindfulness at SHACS every Monday 4:15-4:45
- Any organized exercise. (See previous eboards for a list.)
- 60 minutes of some solitary self-care activities that are unrelated to
academics or work. Your email reflection must explain how
the activity contributed to your wellness.
- 60 minutes of some shared self-care activity with friends. Your email
reflection must explain how the activity contributed to your wellness.
- Wednesday the 10 at 4pm on Mac Field: Giant Laurel Leaf. (Free t-shirt!)
- Scarlet and Give Back Day next Wednesday/Thursday (I think). If you
don’t have money to donate, let me know and I will give you $5 to donate
on Monday.
Other good things
- Because you live in Iowa, presidential candidates come through. Beto
O’Rourke is coming to Hotel Grinnell today at 5:30. Ask about the
hacker collective he was in.
Friday PSA
- Don’t park in the loading zone.
Questions
Sorted linked priority queues
- Where we were: We’d written something, but hadn’t tested it because
Eclipse is evil.
- What I did: Fixed the Eclipse problem by changing the order of
loading of libraries. (I’ll show you.)
- What next? Run tests, Correct code.
- Detour: Eclipse remains evil.
Array-based queues
- Issue one: Expansion
- Issue two: Remove method for iterator
Question: When you are removing a value, why set things to null?
- Helps us catch errors earlier; when you see a null, something is probably
wrong.
- Allows the Java garbage collector to get rid of unnecessary stuff.
- “Feels right”
Question: Sometimes it’s faster to shift right, rather than left. Should
we do that?
- Perhaps. But I’d rather get something that I’m confident is correct
first.
Important morals:
- Draw pictures
- Run code by hand
- Figure out what you want to do
- Check some parts of correctness
- Find missing parts
- Debugger is your friend (especially if you make predictions)
- And probably easier than print statements
- It’s easy to make minor mistakes; having ways to find them are important
- Having other eyes is normally good (less applicable on exams, but you
can rely on my eyes)
- Writing tests that you can observe easily is useful
- Arrays of strings are easier to look at than arrays of ints
- (Arrays of ints may be easier to build)
- Lots of different examples can be helpful
More testing
[Skipped]