for(int i=0; i<size; i++)

[Sentenryu]

silly tokens does depend on the reader. for me, it's more clear what you mean if you use "i" than if you use "loop", but that's because i'm used to the former.

I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

[PIEBALDconsult]

Yes, quite. BASIC in 1983, Pascal in 1985, COBOL in 1986, Fortran (77?) in 1987. But BASIC is the only one I've been paid to use, COBOL and Fortran I only touched in college, and Pascal I haven't used at all since becoming comfortable with C. C# pays the bills now.

[PIEBALDconsult]

Exactly. Know your audience. :thumbsup:

[Member 9975613]

*legacy coder detected* why exactly is "loop" harder to read then "i"? Cant you read? ;)

Copy, paste, compile, erase

[Carlosian]

Yes, as others have said for many it was a carryover from FORTRAN. Nothing formal that I know of, just using i in FORTRAN and then out of habit using it in 'C' as programmers moved over to that and other newer languages.

[R Giskard Reventlov]

Bit like f u n e x? (You'll need to look that up if you don't know what I mean). Using i is so 20th century.

"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." Red Adair. nils illegitimus carborundum me, me, me

[OriginalGriff]

mark merrens wrote:

Using i is so 20th century.

That and Apple will probably patent it before long...

The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)

[Sentenryu]

i think it's alread patented...

I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

[Lost User]

When I first learned about mathematical functions f(x)(a dozen years before my first programming class) I was told mathematicians used "i" for the first incrementing variable, "j" for the next and so on. When I started to learn programming languages, a FORTRAN professor (FORTRAN as in "FORmula TRANslation") who (of course) was a member of the Math department, said something along the lines of "This is not the theology department but using anything other that "I" for the first incremental etc is heresy. Those who want to use 'meaningful words' should consider being English or Philosophy majors and take Professor So-and-So's COBOL class." So, 'I' as an index did not start with FORTRAN, it started before FORTRAN, but it fit nicely because those who used FORTRAN knew its meaning from math studies.

[Member 4608898]

It is from Fortran. Integers were i to n, everything else was real. i happened to be the very first integer letter. Everyone unknowingly just followed Fortran.

[Nicolas Dorier]

Maybe you'll also be interested about the story of the unknow 'x' in math : Explanation on ted talk[^] ;)

[robocodeboy]

Yes, it is so: i, j and k are standard notation for mathematical arithmetic progressions and series. From well before FORTRAN. But FORTRAN was designed by mathematicians, so we programmers are carrying over the notation. a,b,c -> constants x,y,z -> unknown terms (or real coordinates in cartesian plane) k,j,i -> INTEGER indexes or vector coordinates. I think Gauss was already using this conventions, more than 100 years ago. Gauss wins. As always.

[peterchen]

Fortran probably got it from math. Now math... I don't know.

ORDER BY what user wants

[DanielSheets]

I've always used 'x'. Why? Because a "Programming in C" book I started with used it. So I just got used to it I guess.

[DerekT P]

It was also a feature of some early BASIC implementations. There were 26 variables available; A through H were floating point, I through P (??) were integers; R(??) through Z were also floating point. The only explicit type declarations were to suffix one of the single-letter variables with the $ symbol to indicate string. "I" was commonly used for loop control as being the first integer variable. It's a habit I learned in the 1960s and I still use it (very occasionally). Old habits die hard...

[Bikash Prakash Dash]

while(life!=death) { age++; research++; development++; }

[The Nightcoder]

Hi, Others have said this, but it deserves to be repeated: This is classical math (handwritten, typed or printed), from a couple of centuries before the advent of computers. It's pretty natural that it was adopted by most mathematically-oriented computer languages (and, consequently, by later languages), and it also explains why it feels natural to most programmers (who have read any math - which should be a reasonable expectation) even today. indices: i, j, k (don't remember how it goes on after that quantities: n, m (then p, q if I remember correctly - o can be confusing). dimensions: x, y, z, t, (xi), (eta), (theta). I don't remember what happens when we run out of letters for indices and quantities, but if I remember correctly these sequences also continue with greek letters. So:

for (i = 0; i < n; i++)
{
for (j = 0; j < m; i++)
{
for (k = 0; k < p; k++)
{
}
}
}

Pretty straightforward. And Newton would have understood it without thinking... :)

Peter the small turnip (1) It Has To Work. --RFC 1925[^]

[Lutoslaw]

AspDotNetDev wrote:

From this, we can ascertain the correct letters to use for each new level of loop nesting: ijklouhmpygntfbrdvescwaxqz.

How deep did you go into the spiral? I usually stop on the 'g'.

Greetings - Jacek

[AspDotNetDev]

I've never had a need to go past "c".

Thou mewling ill-breeding pignut!

[Lutoslaw]

You should be women, and yet your beards forbid me to interpret that you are so.[^]. Awesome.

Greetings - Jacek