Thing is, you usually define all your variables. At least we do in engineering (of physical variety, rather than software).

Mostly because we can't expect everyone reading the calculation to know, and that not everyone uses the same symbols.

Not explaining each variable is bad practice, other than for very simple things. (I do expect everyone and their dog reading a process eng calc to know PV=nRT, at a minimum).

Just like (in my opinion) not defining industry specific abbreviations is also bad practice.

Mathematicians don't do this? Shame on them.

Using full names like that might be fine for explaining a physical rule, or stating the final result of some calculation - but it certainly would be cumbersome and difficult for actually carrying out the calculations. In many cases we already fill pages with algebra showing how things can be related and rearranged to arrive at new results. That kind of work would be intractable with full word names for the variables, partially because you'd be constantly spilling off the end of the page trying to write the steps; but also because having all that stuff would actually obfuscate what you are trying to do - which is algebra. And during that process, the meanings and values of the pronumerals is not as important has how they interact with each other. So the names are just a distraction.

For setting up an equation, and for stating the final result, the meanings of the variables are very important; but during the process of manipulating the equations to get the result you want the meanings of the letters are often ignored. You only need to know that it is something that can be multiplied, or inverted, or subtracted, or whatever. Eg. suppose I want to rearrange to get the velocity. I don't care that I'm dividing both sides by the air density times the drag coefficient and the area... I'm just dividing ρCA, which is an algebraic blob whose interpretation can be saved for some other time.

Try to write the above with pen and ink and then tell me if you can read it back yourself.

Single letters is not a good system but it was the less bad one.

I would have quit math if I had to do algebra with names instead of letters.

/s?

Try writing 20 algebraic manipulations of the equation on paper and you’ll quickly understand why it’s written that way.

The bottom is absolutely not more readable, and it's much more difficult to work with.

Kids these days have it so easy, pshh

It's not. PHP used to use the function length as hash buckets, so by having evenly distributed lengths the execution time was faster. No idea where GP came up with that.

C is a little older than namespacing and object orientation. C++ wasn't even a glimmer in Bjarne's eye when these conventions were laid down.

And yes, having to google it is part of the design. Originally C programmers would have had to read actual manuals about this stuff. Once you learn the names you don't really forget so it works well enough even now for ubiquitous standard library functions.

And yet, C was an ergonomic revelation to programmers of the time. Now it's the arcane grandpa that most youngsters don't put up with.

How on earth should a newcomer know that the letter “n” in that word stands for number without having to google it?

By looking at the difference between strcpy and strncpy. Preferably, though, you should simply learn C before writing C.

The gist of is is that strcpy takes a null-terminated string and copies it somewhere, while strncpy takes a zero-terminated string and copies it somewhere but will not write more than n bytes. strncpy literally has exactly one more parameter than strcpy, that being n, hence the name. If n is smaller than the string length (as in: distance to first null byte) then you're bound to have garbage in your destination, and to check for that you have to dereference the pointer strncpy returns and check if it's actually null. Yay C error handling.

In retrospect null-terminated strings were a mistake, but so were many other things, at some point you just have to accept that there's hysterical raisins everywhere.

man strncpy