The History of "i" [modified]
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
Hockey wrote:
But is it true?
Almost certainly. And if anyone tries to make me stop using it, then "Absolutely!" ;) Here's a handy Wikipedia topic...
---- Scripts i've known... CPhog 0.9.9 - make CP better. Forum Bookmark 0.2.5 - bookmark forum posts on Pensieve Print forum 0.1.1 - printer-friendly forums
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I thought i/j/k were commonly used in mathematical circles, and so they just moved in to code. Christian Graus - Microsoft MVP - C++
You are joking, right? http://en.wikipedia.org/wiki/Fortran[^] Refer to: The standard FORTRAN joke "GOD is REAL (unless declared INTEGER)." The joke works because, in the absence of an IMPLICIT INTEGER declaration (setting the letter range of integers) or an explicit declaration of a variable giving its type, variables beginning with the letters I through N were automatically considered to be integers, while A through H and O through Z were considered to be real numbers. I, being the first "available" integer in the list of available integers, was commonly used as a loop index. ............................. There's nothing like the sound of incoming rifle and mortar rounds to cure the blues. No matter how down you are, you take an active and immediate interest in life. Fiat justitia, et ruat cælum
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
Hockey wrote:
You know the ubiqious "i" found in almost every example of a for loop for newbies?
I have always used
xfor that. It's the new-old-cool thing. :) Jeremy Falcon -
You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
This brings back memories from the times there was no i.
FOR n=0 TO 5 ... NEXT n:) regards, Mircea Many people spend their life going to sleep when they’re not sleepy and waking up while they still are. -
Hockey wrote:
You know the ubiqious "i" found in almost every example of a for loop for newbies?
I have always used
xfor that. It's the new-old-cool thing. :) Jeremy FalconJeremy Falcon wrote:
I have always used x for that. It's the new-old-cool thing.
:shudder: except that x/X has spatial relationships automatically associated with its use. X and Y on a graph, X,Y,Z in 3D space. When I see x, I see spatial expectations. Personally I think that the use of 'i' comes from deeper inside. Is it the choice of 'i' because of the word integer or is the choice of 'i' as the first integer in Fortran because of a more narcissistic mathematical perspective. :rolleyes: _________________________ Asu no koto o ieba, tenjo de nezumi ga warau. Talk about things of tomorrow and the mice in the ceiling laugh. (Japanese Proverb)
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This brings back memories from the times there was no i.
FOR n=0 TO 5 ... NEXT n:) regards, Mircea Many people spend their life going to sleep when they’re not sleepy and waking up while they still are.What do you mean by "the times there was no i"? :~ Cheers, Vikram.
I don't know and you don't either. Militant Agnostic
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
Math and Physics use "common meanings" for many variable names and symbols. Even though it is important to declare them (as they are overlapping and not wholly universal), if you just scribble down something, often the meaning is implied. At the very least, each publication uses a "consistent" set. Different areas use overlapping sets of symbols (which makes cross-disciplinary papers often a pain). Some, like the lambda are very... promiscuous: you like to use them, but you never trust them. The machanisms - the writer is expected to be consistent, following standards, so the reader can easily understand the meaning from context without "reading" the declarations - are very similar to naming rules in software. Fortran makes mathmaticians happy, which were the first guys using computers anyway. Math was the typical playground for coder brains back when computers were not there. So for me, having written thoudans of "Sum/Product over i=1..n of foo", there is no real surprise here.
Some of us walk the memory lane, others plummet into a rabbit hole
Tree in C# || Fold With Us! || sighist -
You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
i, j, k as loop variables are as natural as x, y, z are for describing points in 3space. You know immediately what the intent is, or maybe I've been around the block a few too many times. Just my humble opinion, of course...
- S 50 cups of coffee and you know it's on!
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
In mathematics, i, j, and k are universal - they are used as integers, indices and to designate imaginary axes for vector quantities. This bled over into FORTRAN when computers were run almost exclusively for mathematicians and has stuck for decades. The use of n is a fairly new development, but it was only a matter of time before we ran out of integers. Fortunately, x and y are still usable for real numbers, and one has to grant them credit - there are an awful lot of real numbers. These valiant variables don't get half the credit they deserve... Engineers have done what we can to preserve the available pool of numeric variables. We use x, y, and z to designate unit vector directions, thereby reducing the load that i, j, and k have to carry. Recognizing the need to conserve, we have also adopted the variable s to designate the special value jw, mainly because it makes the math a lot easier. "...a photo album is like Life, but flat and stuck to pages." - Shog9
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In mathematics, i, j, and k are universal - they are used as integers, indices and to designate imaginary axes for vector quantities. This bled over into FORTRAN when computers were run almost exclusively for mathematicians and has stuck for decades. The use of n is a fairly new development, but it was only a matter of time before we ran out of integers. Fortunately, x and y are still usable for real numbers, and one has to grant them credit - there are an awful lot of real numbers. These valiant variables don't get half the credit they deserve... Engineers have done what we can to preserve the available pool of numeric variables. We use x, y, and z to designate unit vector directions, thereby reducing the load that i, j, and k have to carry. Recognizing the need to conserve, we have also adopted the variable s to designate the special value jw, mainly because it makes the math a lot easier. "...a photo album is like Life, but flat and stuck to pages." - Shog9
Roger Wright wrote:
The use of n is a fairly new development
I think n might be a hungarian notation artifact, meaning "number". I have found it it in a lot of my old code. :-O
- S 50 cups of coffee and you know it's on!
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What do you mean by "the times there was no i"? :~ Cheers, Vikram.
I don't know and you don't either. Militant Agnostic
Vikram A Punathambekar wrote:
What do you mean by "the times there was no i"?
'i' is a very recent letter. Discovered in 1984 by a French astrologer I believe :rolleyes:
Ryan
"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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You know the ubiqious "i" found in almost every example of a for loop for newbies? On another forum were having this disscussion (sorta)... I said (I believe I read it in an C K&R book) that it's because it's simply an alias for Index which is what "i" is usually doing in a for loop...?? Someone else says it has to do with: They are from general Summation Notation that, like many other mathmatical notations, worked its way into early languages -- specifically Fortran (remember its FORMula TRANSlation) I never would have guessed :P Cheers :) It's frustrating being a genius and living the life of a moron!!! -- modified at 21:18 Wednesday 4th October, 2006
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Vikram A Punathambekar wrote:
What do you mean by "the times there was no i"?
'i' is a very recent letter. Discovered in 1984 by a French astrologer I believe :rolleyes:
Ryan
"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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I thought i/j/k were commonly used in mathematical circles, and so they just moved in to code. Christian Graus - Microsoft MVP - C++
i is reserved for sqrt(-1) cheers, Chris Maunder
CodeProject.com : C++ MVP
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Rage wrote:
"i" like "i"nteger, or "s" like "s"tring
Much like hungarian notation, which I happen to like (I'm not hungarian), but am slowly being converted to camelCase (I'm not a camel either).
- S 50 cups of coffee and you know it's on!
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i is reserved for sqrt(-1) cheers, Chris Maunder
CodeProject.com : C++ MVP
Chris Maunder wrote:
i is reserved for sqrt(-1)
We're not going to start this discussion again...are we? :~
They dress you up in white satin, And give you your very own pair of wings In August and Everything After
I'm after everything
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I normally throw spaghetti up against the wall. Then, when I see an interesting pattern, I write it down. And that's how I discover new letters. Coming up with the pronunciation for those letters is a little difficult though. :rolleyes:
They dress you up in white satin, And give you your very own pair of wings In August and Everything After
I'm after everything
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I normally throw spaghetti up against the wall. Then, when I see an interesting pattern, I write it down. And that's how I discover new letters. Coming up with the pronunciation for those letters is a little difficult though. :rolleyes:
They dress you up in white satin, And give you your very own pair of wings In August and Everything After
I'm after everything
David Stone wrote:
Coming up with the pronunciation for those letters is a little difficult though.
Give the spaghetti to someone who eats with their mouth open and listen to the interesting sounds that emerge :)
Ryan
"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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Rage wrote:
"i" like "i"nteger, or "s" like "s"tring
Much like hungarian notation, which I happen to like (I'm not hungarian), but am slowly being converted to camelCase (I'm not a camel either).
- S 50 cups of coffee and you know it's on!
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Chris Maunder wrote:
i is reserved for sqrt(-1)
We're not going to start this discussion again...are we? :~
They dress you up in white satin, And give you your very own pair of wings In August and Everything After
I'm after everything
David Stone wrote:
We're not going to start this discussion again...are we?
What discussion? :-O
Ryan
"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
