[dsfuoi]

I think the style should be avoided; code shouldn't be compact and variable names should be descriptive.

Artificial example:

    for( int i = 0 ; i < c+j ; i += b )

should be:

    for( int count = 0 ; count < sum+extra ; count += skip )

It may be allowed to use i in place of count here, but this is the only place where single name variables should be permitted and only if i is really just a simple array index iterator.

[jimjimjim]

There should always be a balance between brevity and being too verbose.

all single letters = bad, java style thisIsALoopCounter = bad.

and in the c world i is almost universally understood to be used as a loop counter and index. If I came across 'count' in a c code I (briefly) might think it was related to a count of items in an array or similar.

[dsfuoi]

I agree. The problem is that those single character names get abused and you end up with code that consists only of them, including the function arguments, which is the worst.

[GregBuchholz]

I hope you don't have a stroke:

https://github.com/jsoftware/jsource/blob/master/jsrc/cip.c

...just one of the many source files that make the interpreter for the J language.

[dsfuoi]

The 'style' even leaked out to file naming: a.c, ab.c, af.c, am.c, c.c, ca.c, cc.c, cd.c, cf.c, ...

Brilliant!

I doubt that this is either serious (unobfuscated) or handwritten code though.

[GregBuchholz]

No, it really is the hand-written source code for the J language (http://jsoftware.com/) interpreter. You may also enjoy:

https://news.ycombinator.com/item?id=2336749

http://code.jsoftware.com/wiki/Essays/Incunabulum

[kps]

For the record: http://www.tuhs.org/cgi-bin/utree.pl?file=V2/c/nc0

[tmuir]

Even "i" can be changed to "index". My rule of thumb is this: If you wouldn't use the abbreviation when speaking, don't use it when coding.

I don't understand why 'i' has been given a pass. The argument boils down to saved keystrokes. Typing is not the bottleneck.

[dllthomas]

> I don't understand why 'i' has been given a pass.

Because it is well enough established (in both programming and mathematics) that it communicates literally no less information to the reader than "iterator" or "index" would in the same context.

> The argument boils down to saved keystrokes.

Not at all. I, for one, find it easier to see the shape of the whole expression when the variable names are shorter.

[kps]

Yes; prolixity yields clarity in programming about as much as in prose. The old quip needs an update: a modern programmer can write COBOL in any language.

[kleiba]

My guess would be that it derives from the mathematical notation for sums.

But apart from that, I think using i,j,k as index variables in for-loop has become such a de-facto standard that I would only prefer long names such as "count" or "index" in situations where multiple indices may cause confusion. But then I'd probably use even more specific names than "count" or "index".

[Gibbon1]

> I don't understand why 'i' has been given a pass.

The reason is that in FORTRAN variables starting with i, j, k..n were defined as integers.

Back in the day I learned fortran first, then basic. People that learned basic first often would use the letter 'a' as a loop index instead of 'i'

Now days I still use 'i' but often use indx instead because my editor doesn't highlight single letter variables easily.

[majewsky]

I'm okay with "i" (like others said, it's a well-known shorthand for "iterator" or "index") but I often use "idx" because it can easily be combined with other words in nested loops (e.g. "rowIdx" and "columnIdx").

[dsfuoi]

I agree, and I have calculated this a while ago this based on average number of lines a programmer writes in 8 hours. I don't have the actual numbers but unless you type slower than ~30 words per minute, speed it isn't a bottleneck.

I have been using index instead of i in while loops lately. It's surprisingly concise.

[husted]

When I started to program in C I used "n" for the longest time, simple because it was quicker on to type on my first computer; "Next N" was a quick two taps on the N key. Guess the platform :-)

[teddyh]

A ZX80, ZX81 or ZX Spectrum.