A binary tree is one way of preparing data, usually for sorting. Each node can have a left, right, or both, children.

  A
 / \
B   C
   / \
  D   E

“Inverting the tree” means swapping the children for each node, so that the order that the nodes are visited is reversed. Depending on whether you want to copy the tree or swap it in place then the algorithm is different. C++ provides iterators too, so providing a “order reversed” iterator can be done efficiently as well.

You’re going to have to visit every node and do at least one swap for every node, and an efficient algorithm won’t do much more than that. Bring unable to do it suggests that the student programmer doesn’t understand stacks or recursion yet, so they’ve more to learn.

Programming a robust global date-time system and having a transparent conversation between metric and *imperial/traditional" units is just a warm-up to show that you can work with the truly demented currency system. Make sure everything is rounded off to the nearest whole ha’penny.

You can only store rational numbers as a ratio of two numbers, and there’s infinitely times more irrational numbers than rational ones - as soon as you took (almost any) root or did (most) trigonometry, then your accurate ratio would count for nothing. Hardcore maths libraries get around this by keeping the “value in progress” as an expression for as long as possible, but working with expressions is exceptionally slow by computer standards - takes quite a long time to keep them in their simplest form whenever you manipulate them.

To be fair, compiling C code with a C++ compiler gets you all the warnings from C++'s strong-typing rules. That’s a big bonus for me, even if it only highlights the areas of your C that are likely to become a maintenance hazard - all those void* casts want some documentation about what assumptions make them safe. Clang will compile variable-length arrays in C++, so you might want to switch off that warning since you’ve probably intended it. Just means that you can’t use designated initialisers, since C++ uses constructors for that and there’s no C equivalent. I’d be happy describing code that compiles in either situation as “C+”.

Also stops anyone using auto, constexpr or nullptr as variable names, which will help if you want to copy-paste some well-tested code into a different project later.

Man alive, don’t get the managers working with audio. “Doubling the stream” might work if you’re using a signed audio format rather than an unsigned one, and the format is in the same endianness as the host computer uses. Neither of which are guaranteed when working with audio.

But of course, the ear perceives loudness in a logarithmic way (the decibel scale), so for it to be perceived as “twice as loud”, it generally needs an exponential increase. Very high and low frequencies need more, since we’re less sensitive to them and don’t perceive increases so well.

Finish the transition from X to Wayland?

“Register bit twiddling.” Setting all the modes that all their various cards can operate in, with the associated code for sending the bit updates over the connection bus. Tedious stuff that’s very prone to copy-paste errors if written by hand.

At some point you have to take AMDs word for it that these codes = this functionality, but if the right graphics come out then it can’t be so wrong.

Because if you disable browser autocomplete, what’s obviously going to happen is that everyone will have a text file open with every single one of their passwords in so that they can copy-paste them in. So prevent that. But what happens if you prevent that is that everyone will choose terrible, weak passwords instead. Something like September2025! probably meets the ‘complexity’ requirement…

A bit like when we renamed all the master/slave terminology using different phrasing that’s frankly more useful a lot of the time, I think it’s about time we got rid of this “child” task nonsense. I suggest “subtask”. Then we can reword these books into something that no-one can make stupid jokes about any more, like “how to keep your subs in line” and “how to punish your subs when they’ve misbehaved”.

Well now. When we’ve been enforcing password requirements at work, we’ve had to enforce a bizarre combination of “you must have a certain level of complexity”, but also, “you must be slightly vague about what the requirements actually are, because otherwise it lets an attacker tune a dictionary attack against you”. Which just strikes me as a way to piss off our users, but security team say it’s a requirement, therefore, it’s a requirement, no arguing.

“One” special character is crazy; I’d have guessed that was a catch-all for the other strange password requirements:

• can’t have the same character more than twice in a row
• can’t be one of the ten-thousand most popular passwords (which is mostly a big list of swears in russian)
• all whitespace must be condensed into a single character before checking against the other rules

We’ve had customers’ own security teams asking us if we can enforce “no right click” / “no autocomplete” to stop their users in-house doing such things; I’ve been trying to push back on that as a security misfeature, but you can’t question the cult thinking.

As an example of a language that many people are familiar with, which is likely to be in long-term use where maintainability is most important, and which can almost read like pseudocode anyway, sure - probably the best ‘real language’ choice.

You can write an unmaintainable fucking mess in any language. Rust won’t save you from cryptic variable naming, copy-paste code, a complete absence of design patterns, dreadful algorithms, large classes of security issues, unfathomable UX, or a hundred other things. “Clean code” is (mostly) a separate issue from choice of language.

Don’t get me wrong - I don’t like this book. It manages to be both long-winded and facile at the same time. A lot of people seem to read it and take the exact wrong lessons about maintainability from it. I think that it would mostly benefit from being written in pseudocode - concentrating on any particular language might distract from the message. But having a few examples of what a shitfest looks like in a few specific languages might help

My old job had a lot of embedded programming - hard real-time Z80 programming, for processors like Z800s and eZ80s to control industrial devices. Actually quite pleasant languages to do bit-twiddling in, and it’s great to be able to step through the debugger and see that what the CPU is running is literally your source code, opcode by opcode.

Back when a computers were very simple things - I’m thinking a ZX Spectrum, where you can read directly from the input ports and write directly into the framebuffer, no OS in your way just code, then assembly made a lot of sense, was even fun. On modem computers, it is not so fun:

• x64 is just a fucking mess

• you cannot just read and write what you want, the kernel won’t let you. So you’re going to be spending a lot of your time calling system routines.

• 99% of your code will just be arranging data to suit the calling convention of your OS, and doing pointless busywork like stack pointer alignment. Writing some macros to do it for you makes your code look like C. Might as well just use C, in that case.

Writing assembly makes some sense sometimes - required for embedded, you might be writing something very security conscious where timing is essential, or you might be lining up some data for vectorisation where higher-level languages don’t have the constructs to get it right - but these are very small bits of code. You would be mad to consider “making the whole apple pie” in assembly.

Got this installed on all my work machines - if you’re wanting to stick a screenshot on Jira or Slack with a couple of arrows, wavy lines, or a bit blurred out then it’s dead quick and has just the functionality that you need. Yes, it’s simple and lacks a lot of ‘power tools’. Sometimes that’s just what you need, tho.

Think you’re understating it there. Network call takes milliseconds at best. Function call, if the CPU has correctly predicted the indirect branch, is basically free, but even if it hasn’t then you’re talking nanoseconds. It’s slower by millions of times.

I used to work with a Greek guy called Argyros Argyros - cool guy, but suspect he was an outlier. Named after his dad, so certainly some people are named that way. Icelandic for instance would traditionally use “Given Name” “Patronym from father” - Magnus Magnusson was quite famous in the UK; Björk Guðmundsdóttir might be the most famous internationally, but she’s not a “double”. There’s quite a few cultures - Hungarian, Chinese, Japanese, … - that write their names as “Family Name” “Given Name” as opposed to the other way around, if that’s what you mean?

That’s almost exactly the problem. English uses helper words exclusively for future tense, and indeed, helper words like ‘to’ to form an infinitive. ‘Will’ is the helper word to show that something is a fact, that it is definite - grammatically, it is indicative. (The sun will rise tomorrow.) ‘Would’ is the helper word to show that something is an opinion, or dependent on something else - grammatically, it is subjunctive. (If you push that, it would fall; if it was cheaper, I would buy it.)

Spanish has both helper words for future tense (conjugations of ‘ir’, analogous to ‘going to’, often used in speech) and straight-up conjugations for future tense (doesn’t exist in English; often used in writing). It also conjugates verbs differently if they’re indicative, subjunctive, or imperative (asking or telling someone to do something). This is how Spanish manages to have fifty-odd ways to conjugate every verb, which is very confusing to English speakers who make do with three ways and helper words.

Translating a ‘future tense sentence’ for Duolingo requires you to have psychic powers about whether something is fact or opinion, which helper words are wanted, and so on, and it usually comes down to guessing between multiple ‘correct’ answers, which Duo will reject all but one of.

Absolutely this. I’d have argued that ‘every day’ is a more idiomatic translation than ‘daily’, and what native speakers would say, but that’s irrelevant. English tends to emphasise the end of sentences as the most important part, so all these translations are correct depending on the nuance that you intend:

• Daily in Hamburg, many ships arrive (as opposed to eg. cars, or few ships)
• Daily, many ships arrive in Hamburg / Many ships arrive daily in Hamburg (as opposed to eg. Bremen)
• Many ships arrive in Hamburg daily (as opposed to eg. weekly)

Wouldn’t question any of those constructions as a native speaker. In fact, original responders’ example was why I gave up on Duolingo myself originally, some years ago. Translating ‘future tense’ sentences from Spanish into English or back again is always going to be a matter of opinion, since English doesn’t have the verb conjugations that Spanish does. Guessing the ‘sanctified answer’ is tedious, when a lot of the time it’s not even the most natural form of a sentence.

I wish there was a linter that stopped my colleagues from adding in a half-gigabyte of Apache Spark artifacts to go with a single line of code, which makes the product impossible to deploy to customers; or to implement another fucking O(n^2) algorithm that flies through the test suite and craps out in production; or our placement students from trying to get ChatGPT shit through code review. Sigh.

I also fucking hate checkstyle, or any of its friends like Google’s spotless; sometimes you want to format your code so that the underlying thinking is more obvious, perhaps to highlight how some parts are different and make things that are not as you would expect stand out, but no.

Tools that generate warnings, for the assistance of human reviewers? Great. Tools that generate errors, so that you have to go stupid shit to keep a machine happy? Not so great.

Yeah - pure functions and immutable data aren’t always the right answer, but appreciating that they’re damn good most of the time is a good first step. Writing obvious code that does exactly what it appears to do at first glance and not one thing more? Your colleagues will thank you when they have to work with your stuff.