Comment by patrickyeon | Hacker News Reader

Comment by patrickyeon | Hacker News Reader

A few years ago, I saw a classroom video (I would guess ~8-10 year olds, in the American public school system) as a demonstration of a teacher's technique called "my favourite wrong answer". She would have them solve a problem (a math problem, in this particular case), collect the answers, show the distribution of the answers, and then pick out one answer (possibly with the student's name redacted) as her "favourite wrong answer". And then she would work through why she liked it so much with the students. In the examples, it was cases where the person was on the right track, but then made an incorrect, but justifiable by _some_ standard, step in solving it.

It seemed like a good way to really try to understand where someone's comprehension broke down. It felt like it added some legitimacy to the students who got the answer wrong, if others could look at it and go "oh, I see why you thought that!" instead of just "wow try to get it right next time". I believe it's part of what good teachers (not limited to school educators, mind you) are doing all the time: looking for the student's gaps and trying to correct those, instead of just repeating the lesson that has already failed to stick.

I guess this just makes me think of that teacher, trying to work out what her pupils were misunderstanding, by looking at their answers.

Where I was teaching, we've started doing code review in classroom in basically the same spirit.

The amount of students prevents us from real selection, instead we take exercises which failed tests (and that are not empty) and explain what was wrong, identify common mistakes or bad style and try to make it correct.

We had a very good feedback on this. And we saw an evolution in students' code. It was way better than trying to do collection of bad practice ...

This is some very good advice! I am teaching a C++ class and am struggling with the quality of the code my students are producing. Their programs output the correct answer, yet the style is really lacking. Periodic code reviews of some selected problems would be extremely useful, thank you for the tip!

> I am teaching a C++ class and am struggling with the quality of the code my students are producing. Their programs output the correct answer, yet the style is really lacking.

I remember trying to help fellow students with their C and C++ assignments back in undergrad, and reading some of their code I got the distinct feeling that most of it was “random-walked” code. Like they tried writing things that looked like C, making random, iterative changes until it compiled. Then once it compiled, made random, iterative changes until the output approached what the expected output would be. Sometimes the functionality ended up right, but with bizarre stuff like: unused variables all over the place, variables assigned then reassigned without using the first value, uses of pointer indirection that look like the student kept adding or removing asterisks until it didn’t crash, elaborate class hierarchies that went unused, etc. It’s like the Infinite Monkeys Eventually Producing Shakespeare thing but with programming assignments.

Yes, that's exactly my own experience. Moreover, we are forced to use ROOT [1] to compute histograms and create graphics: its weird use of OOP makes the students think that they have to use classes even to implement simple functions (e.g., printing a list of values).

[1] https://root.cern.ch/

> uses of pointer indirection that look like the student kept adding or removing asterisks until it didn’t crash

Oh c'mon, that's practically a right of passage when learning C or C++ for the first time, especially if you're new to programming as a whole :-)

Now you're making me think about my specification and verification professor from years ago. A lot of the exercises had us specify stuff with some formalism. Something like a finite state machine for a 3 digit combination lock, or pre- and post conditions of algorithms, loops and such.

The tutorials about these exercises were really cool, because we'd spend a short time wrapping up mistakes in the notation. But then he usually classified and grouped the different solutions according to the design decisions made and it would evolve into large discussions about tradeoffs of choices.

Someone might go "Well I figured the FSM would be smaller if I fail on the first wrong number, and it'd be user friendly because it fails early", and someone objects "But that's insecure!" and someone else figures "And also it'd be much easier to write up a control circuit that always expects three digits" and eventually everyone is confused if we're looking at the user input as a stream of tuples of three digits, instead of looking at the last three digits in a stream of digits.

It was a very instructive class.

The issue with really learning computer science outside top well known schools is that you're basically on your own for education (or worse if taught wrong). Open source software somewhat teaches you things but usually by trial by fire.

Really? I went to a non-top school and putting aside the formal education component, I felt like I also had plenty of co-learning. That is, I remember many study groups where we helped each other learn, including for programming.

I certainly didn't feel like I was on my own.

Similar experience here, my university helped people form study groups near final exams and had a "homework club", where final year and grad students were paid to help first and second year students with their assignments for a couple hours a week, and people were encouraged to meet each other in that club and find "study buddies" (but no-one actually called it that, because ugh)

Covered everything from the programming to the multivariable calculus and data science (much harder to find students confident enough to teach others for those last two though)

I went to an unknown state school and I got a damned fine education. Top schools don’t have a monopoly on good teachers or good students, not even remotely close.

> really learning computer science outside top well known schools

Eh... no. It's not 1975 anymore. This knowledge is widely distributed.

Moreover, the on your own for education bit, even if true is a bit dishonest. Being "on your own" with this in 2018 is absolutely incomparable to how it was 10 years ago, much less 20 or more. The amount of materials accessible for free or extremely cheap is mind-blowing to people who had to learn programming from a single (physical) copy of Stroustrup's "The C++ Programming Language".

when I contemplate the available resources for a starting programmer, my mind is always stunned.

That isn't totally wrong, but I think you drew the line in the wrong place. There are numerous less-known schools that are OK, but a typical community college or liberal arts school isn't going to deliver the goods. State universities are sometimes good.

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