Old age shows its mark...
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I have never touched Fortran or Cobol and I use the same conventions, I have no idea where I picked it up from as I learnt to code on a commodore 64 and then from a SuperBase manual.
Never underestimate the power of human stupidity - RAH I'm old. I know stuff - JSOP
Some early BASIC versions allowed up to 26 numeric variables; i through m (?) were integers, everything else floating point. It's a reflection of the generosity of 26 variables that in practice most of us only ever needed i, j, k as integers; we really were spoiled for choice.
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Okay, I was writing some code and noticed that I was using 'i','j', and 'k' for looping indices - it shook me that I still retained that habit. :doh: Then I thought: "Who cares? They do the job" :laugh:
A human being should be able to change a diaper, plan an invasion, butcher a hog, navigate a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects! - Lazarus Long
Mathematicians used i, j and k as indexes long before Babbage's Analythical Machine. It did not come with Fortran. When I was a student, the professors insisted on long, descriptive names in our programming hand-ins. I looked over the shoulder of one of my classmates: His integer variables where named I01, I02,... float variables F01, F02... I shook my head: Prof xxx will explode into small pices when he sees that code! My classmate smiled back: Oh no, of course I make a global subsistute of I01 with NumberOfFruitBaskets, I02 with NumberOfApplesPerBasket, F01 with AverageWeightPerApple and so on, but I can't be bothered with typing those long names when I develop the program! (He was the brightest kid in class, and certainly had the mental capacity to keep the asossication between F01 and the average apple weight.) In my current job, one group revising our coding standards suggested that code lines were restricted to at most 72 characters (they were serious about that!). My project asked for an exception, as we had rules for the naming of cross-module #define constants that in some cases lead to identifiers exceeding the 72 char limit. ... I think that is going a little bit too far in the other direction.
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Old FORTRAN habits die hard ... I do the same, but at least I have to declare them these days. Old FORTRAN programmers never die, they RETURN to caller
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
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Old FORTRAN habits die hard ... I do the same, but at least I have to declare them these days. Old FORTRAN programmers never die, they RETURN to caller
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
God is real, unless declared otherwise by an IMPLICIT statement or an explicit declaration. This joke was well known in the late 1970s. For those who never worked with Fortran: IMPLICIT COMPLEX (F-H) would make all variables starting with an F, G or H to be of default type COMPLEX. You could explicitly decare REAL GOD, overriding the IMPLICIT, but if you simply referenced GOD with no declaration, GOD would be COMPLEX. I once spent a full day helping one guy find the cause for his program Fortran behaving in completely crazy ways. I didn't spot it until I single stepped through his program, machine instruction by machine instruction, seing that the compiler referenced two different locations, seemingly selected at random, that should have been a single location. Or ... Searching for the variable name in the source code hit only half of them. In the other half, the letter O was written as the digit 0, and in both the screen and printer fonts the two were almost perfectly identical. Obviously, the coders had used a lot of copy/paste to get that many occurences of 0. In Fortran, you can declare IMPLICIT NONE (at least from Fortran 77 onwards), forcing you to explicitly declare every variable, as in any other decent programming language. But lots of old Fortran programmers hated having to tell in advance that they were going to need this and that variable; they didn't see the point of explicit declaration, and refused to use IMPLCIT NONE. Some programmers are that way even anno 2019, praising their favorite language because variables are implicitly declared. (Or that they don't need braces around composite statements. Or use braces rather than BEGIN END. Or int rather than integer, bool rather than boolean / logical. Or... So don't be too harsh with the old Fortran programmers!)
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Single letter loop counters is not just FORTRAN -- C as well.
But it started in FORTRAN which had implicit typing based on the first letter of the variable name: I to N inclusive were integers, everything else were reals. With no enforced declaration, it became a convention that I, J, K were integer values used in loop guards. C always had compulsory variable declaration, which made typing by variable name irrelevant - and got rid of a lot of errors: NASA "lost" a probe because someone mistyped a comma. What they meant to type:
DO 15 I = 1,100
A loop to Label 15, integer I runs between 1 and 100 inclusive. What was typed:
DO 15 I = 1.100
Because FORTRAN ignored spaces outside strings, this was seen by the compiler as:
DO15I = 1.100
which is a perfectly valid assignment to a brand new variable called DO15I. Since there is no need to declare a variable, the "D" makes it a real variable, and that's completely legal (if rather useless)
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
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God is real, unless declared otherwise by an IMPLICIT statement or an explicit declaration. This joke was well known in the late 1970s. For those who never worked with Fortran: IMPLICIT COMPLEX (F-H) would make all variables starting with an F, G or H to be of default type COMPLEX. You could explicitly decare REAL GOD, overriding the IMPLICIT, but if you simply referenced GOD with no declaration, GOD would be COMPLEX. I once spent a full day helping one guy find the cause for his program Fortran behaving in completely crazy ways. I didn't spot it until I single stepped through his program, machine instruction by machine instruction, seing that the compiler referenced two different locations, seemingly selected at random, that should have been a single location. Or ... Searching for the variable name in the source code hit only half of them. In the other half, the letter O was written as the digit 0, and in both the screen and printer fonts the two were almost perfectly identical. Obviously, the coders had used a lot of copy/paste to get that many occurences of 0. In Fortran, you can declare IMPLICIT NONE (at least from Fortran 77 onwards), forcing you to explicitly declare every variable, as in any other decent programming language. But lots of old Fortran programmers hated having to tell in advance that they were going to need this and that variable; they didn't see the point of explicit declaration, and refused to use IMPLCIT NONE. Some programmers are that way even anno 2019, praising their favorite language because variables are implicitly declared. (Or that they don't need braces around composite statements. Or use braces rather than BEGIN END. Or int rather than integer, bool rather than boolean / logical. Or... So don't be too harsh with the old Fortran programmers!)
I am an old FORTRAN programmer! It was the second language they taught us at Uni - the first (Gawd help us) was COBOL which was enough to put quite a few people right off the whole idea... :laugh:
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
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But it started in FORTRAN which had implicit typing based on the first letter of the variable name: I to N inclusive were integers, everything else were reals. With no enforced declaration, it became a convention that I, J, K were integer values used in loop guards. C always had compulsory variable declaration, which made typing by variable name irrelevant - and got rid of a lot of errors: NASA "lost" a probe because someone mistyped a comma. What they meant to type:
DO 15 I = 1,100
A loop to Label 15, integer I runs between 1 and 100 inclusive. What was typed:
DO 15 I = 1.100
Because FORTRAN ignored spaces outside strings, this was seen by the compiler as:
DO15I = 1.100
which is a perfectly valid assignment to a brand new variable called DO15I. Since there is no need to declare a variable, the "D" makes it a real variable, and that's completely legal (if rather useless)
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
OriginalGriff wrote:
But it started in FORTRAN
Very true! However, I expect a lot more folks frequenting this forum picked the naming habit from C rather than FORTRAN. That would make an interesting poll -- list languages popular before 1990 and get counts of who has done what.
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Mathematicians used i, j and k as indexes long before Babbage's Analythical Machine. It did not come with Fortran. When I was a student, the professors insisted on long, descriptive names in our programming hand-ins. I looked over the shoulder of one of my classmates: His integer variables where named I01, I02,... float variables F01, F02... I shook my head: Prof xxx will explode into small pices when he sees that code! My classmate smiled back: Oh no, of course I make a global subsistute of I01 with NumberOfFruitBaskets, I02 with NumberOfApplesPerBasket, F01 with AverageWeightPerApple and so on, but I can't be bothered with typing those long names when I develop the program! (He was the brightest kid in class, and certainly had the mental capacity to keep the asossication between F01 and the average apple weight.) In my current job, one group revising our coding standards suggested that code lines were restricted to at most 72 characters (they were serious about that!). My project asked for an exception, as we had rules for the naming of cross-module #define constants that in some cases lead to identifiers exceeding the 72 char limit. ... I think that is going a little bit too far in the other direction.
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this style works for me. Its hip like texting acronyms now. You could use i d k instead or f y i. My personal favorite was back when I used VB Dim g as string... It made my programming style quite revealing.
j snooze wrote:
You could use i d k
They would be good for WHILE loops, but not FOR -- because with FOR loops, you do k.
I wanna be a eunuchs developer! Pass me a bread knife!
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Some early BASIC versions allowed up to 26 numeric variables; i through m (?) were integers, everything else floating point. It's a reflection of the generosity of 26 variables that in practice most of us only ever needed i, j, k as integers; we really were spoiled for choice.
My first BASIC experience was with 286 variables: A-Z, A0-A9, B0-B9, ... And 26 string variables: A$ to Z$. I never saw a BASIC so tiny that it had only 26 numeric variables - maybe it existed, but I doubt that any real world problems were solved with that compiler :-). Also, the first Basic compiler I worked with didn't distinguish between integer and float - that was quite common in the early Basic days. I believe that with the Univac 1100 mainframe series Basic, every variable was born as integer, but as soon as it was assigned a float literal value or the result of a non-integer expression, the type was changed on the fly. (So I think it really was an interpreter, not a compiler system.) No Fortran style implicit type by (first) letter.
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I recall that in calculus we would use i, j and k as the iterator variables for summation operators. The exception seemed to be t when it was time but that was more physics applications than the pure math.
And in the grey zone between math and physics: I spent my high school senior year in the US as an exchange student. The physics teacher in my Norwegian high school had stressed that one good reason for using 'v' as a symbol for speed and 'u' as a symbol for voltage is to make it simpler to do complex calcuations as "pure math" without being confused by any physical interpretation of the (partial) expressions. My US physics teacher stressed exact the opposite view: We use 'v' for velocity to make you concious of the meaning of this value within a complex formula! ... He was surprised that we did not use the initial letters of the Norwegian words for those concepts. How can you know what you are calculating, if you ignore the semantics? I do understand his reasoning, but it goes only so far. At some point, you must detach the calculations from the physical interpretation of each value. To take one example: In electronics, I learned to calculate filters, handling both the values and the units, and saw it coming out as a value in seconds (or more commonly: microseconds) describing the filter. I know how I got there, but it never got under my skin how the value ended up as a time. I cannot associate a filter with a time span, the way I can see what a car's speed or mass represents. I can only handle it by treating it as pure math, and learn that the resulting value comes out as microseconds, without grokking it.
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And in the grey zone between math and physics: I spent my high school senior year in the US as an exchange student. The physics teacher in my Norwegian high school had stressed that one good reason for using 'v' as a symbol for speed and 'u' as a symbol for voltage is to make it simpler to do complex calcuations as "pure math" without being confused by any physical interpretation of the (partial) expressions. My US physics teacher stressed exact the opposite view: We use 'v' for velocity to make you concious of the meaning of this value within a complex formula! ... He was surprised that we did not use the initial letters of the Norwegian words for those concepts. How can you know what you are calculating, if you ignore the semantics? I do understand his reasoning, but it goes only so far. At some point, you must detach the calculations from the physical interpretation of each value. To take one example: In electronics, I learned to calculate filters, handling both the values and the units, and saw it coming out as a value in seconds (or more commonly: microseconds) describing the filter. I know how I got there, but it never got under my skin how the value ended up as a time. I cannot associate a filter with a time span, the way I can see what a car's speed or mass represents. I can only handle it by treating it as pure math, and learn that the resulting value comes out as microseconds, without grokking it.
That takes me back to my year as an Electrical Engineering major. The math that would fall out of circuit diagrams was pretty intense. In the end though it felt like hocus-pocus and I couldn't relate so became a Mechanical Eng. major, then a physics major but somehow ended up as an actuary writing programs. "i" is still an oft used loop variable so long as interest rates are not in the context. "grok", haven't heard that in a while. :)
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Okay, I was writing some code and noticed that I was using 'i','j', and 'k' for looping indices - it shook me that I still retained that habit. :doh: Then I thought: "Who cares? They do the job" :laugh:
A human being should be able to change a diaper, plan an invasion, butcher a hog, navigate a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects! - Lazarus Long
In the early 1980s I read an analysis of the time consumption of CDC (mainframe systems) compilers. One of them spent about 60% of the total running time on getting the next source file character to the tokenizer. In the 35+ years since then I have never learnt anything that could fully explain that figure; maybe they had no buffering at any level between the getc() and the pysical disk. That would be crazy, but how can you explain the observations in other ways? That compiler certainly cannot have spent much resources on, say, fancy optimizations! The claim has some substance. I worked with Tcl/Tk in the early days, when the source code was directly interpreted: If a loop was executed a million times, the same source code statements were tokenized and parsed a million times. Whitespace and comments were skipped over a million times. Symbols were looked up a million times. So there were preprocessors removing all comments and unneccessary whitespace, to make the code run significantly faster. Some of these preprocessors also replaced longer variable names with short ones, but due to the extremely dynamic nature of Tcl (you can build a character string at run time, and then execute it as a statement - if you build a string referring to a variable name, it wouldn't find the shorter name). When Tcl introduced bytecodes, speed increased by a significant factor. I have heard similar stories from other developers, using other interpreted languages, and sometimes they argue in favor of short names to speed up interpretation. Today, that is mostly an old myth that won't die: Bytecode compilation, or at least some sort of pre-processing, has become the norm in anything that is called "interpreted" languages. (With no pre-processing, they are commonly called "scripting" languages nowadays.)
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Okay, I was writing some code and noticed that I was using 'i','j', and 'k' for looping indices - it shook me that I still retained that habit. :doh: Then I thought: "Who cares? They do the job" :laugh:
A human being should be able to change a diaper, plan an invasion, butcher a hog, navigate a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects! - Lazarus Long
I have a degree in physics, where we used single letters for every variable, going to Greek for lack of letters, and i,j,k were universally used for counting in equations, usually corresponding to the three dimensions x,y,z. FORTRAN was used for scientific calculations and naturally adopted what scientists use.
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Okay, I was writing some code and noticed that I was using 'i','j', and 'k' for looping indices - it shook me that I still retained that habit. :doh: Then I thought: "Who cares? They do the job" :laugh:
A human being should be able to change a diaper, plan an invasion, butcher a hog, navigate a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects! - Lazarus Long
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well another memory muscle reason for many... before FORTRAN many learned BASIC (back in the day when a school would have 2 or 3 TRS-80 or similar computers, the first version (Model I with 4k RAM) only had single char variables A..Z. Later the Model II (with the massive 16k) allowed 2 letters AA..ZZ. anyhoo it was actually in the Programming Guide (probably inspired from FORTRAN) that suggested I, J, K, L... for "general" integers (in particular FOR loops), (also ref: I for iterator) S, T, U for general strings. "Important" variables used A, B, C (effectively the global variables) suggested sticking to single letters for compatibility with Model I. Some versions of FORTRAN also had that 2 letter limit. "That way you could better determine what any variable was for/about." mock it if you will, but given the naming limitations of the time at least some were already invested enough to come up with some common coding styles. - Nowadays i, j as iterators/offsets even makes appearances in mathematics, - when you see "for (i = 0; ..." you already know the intent (unless you or the programmer are idiot(s), and that's even if it's someone else's code. -- and inasmuch almost makes it better to keep using i, j ... unless you're some sort of purist 'style wanker' who says 'the code may be misunderstood' ..... (and let's face it: such comments are nearly always a reflection of the lack of abilities of the idiot quoting them).
For general strings I kind of like S T F U. :laugh: No offence intended, merely humor.
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Old FORTRAN habits die hard ... I do the same, but at least I have to declare them these days. Old FORTRAN programmers never die, they RETURN to caller
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
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If the next guy (or me) can't figure out what the 'i', or 'j' or 'k' is used for, then the need to get a different job (or take a FORTRAN course!).
A human being should be able to change a diaper, plan an invasion, butcher a hog, navigate a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects! - Lazarus Long
It's funny how we pick up these habits along the way, going from one language to the next. I immediately knew you had programmed in Fortran at some point.
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Not just FORTRAN. We used i, j, and k for loop vars in all my C and C++ classes, too.
If you think 'goto' is evil, try writing an Assembly program without JMP.
As I said earlier: The Lounge[^]
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
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As I said earlier: The Lounge[^]
Sent from my Amstrad PC 1640 Never throw anything away, Griff Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!
