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

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  • T tumbledDown2earth

    I am sure this was one of the hello-world codes for many of us ... But I wonder why the letter "i" .. I mean why on earth? With "a" the leading character why "i" ... After sometime I found out that Fortran language (which was/is historically used for scientific calculations) use "i" as a starting character for all integer type variables, and the quickest varible to write would be "i" Most authors and coders continued to use "i" even in C and then to C++ and then to C#, Java etc ... Is this an interpretation?

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    YDaoust
    wrote on last edited by
    #17

    I tend to use Index instead of i (I definitely like verbose identifiers). And when I need several indexes, like in nested loops, I naturally call them Jndex, Kndex, Lndex... (not kidding). I have not yet come to the point that I use Number and Mumber for counts.

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    • R Rosenne

      AFAIK it started with the first FORTRAN - there were no type declarations then. See https://en.wikipedia.org/wiki/Fortran#FORTRAN[^]

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      greldak
      wrote on last edited by
      #18

      There were but they were implicit. Any variable name beginning with a letter between (and including) the first two letters of INteger was an integer, any other variable was a real.

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      • Y YDaoust

        I tend to use Index instead of i (I definitely like verbose identifiers). And when I need several indexes, like in nested loops, I naturally call them Jndex, Kndex, Lndex... (not kidding). I have not yet come to the point that I use Number and Mumber for counts.

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        Matthew Bache
        wrote on last edited by
        #19

        If it wasn't for our coding standard, I would employ index, jndex... today. I like that idea.

        Matt

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        • B Brady Kelly

          But I shudder to think why someone would venture right across the keyboard for a '1' instead of an 'i'. Yes, dataset.Tables[1] will work, but why, oh the humanity, why, are you not using the table name?

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          Jacquers
          wrote on last edited by
          #20

          It could happen during testing, but I agree that using the table name is better.

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          • T tumbledDown2earth

            I am sure this was one of the hello-world codes for many of us ... But I wonder why the letter "i" .. I mean why on earth? With "a" the leading character why "i" ... After sometime I found out that Fortran language (which was/is historically used for scientific calculations) use "i" as a starting character for all integer type variables, and the quickest varible to write would be "i" Most authors and coders continued to use "i" even in C and then to C++ and then to C#, Java etc ... Is this an interpretation?

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            gholamali Hosseini
            wrote on last edited by
            #21

            i am using 'i' and 'j' for iterating 2D arrays because 'i' and 'j' mean x and y in Cartesian coordinates. :) http://butterfly.blog.ir[^]

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            • M Matthew Bache

              If it wasn't for our coding standard, I would employ index, jndex... today. I like that idea.

              Matt

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              YDaoust
              wrote on last edited by
              #22

              You can use it undercover by means of a macro #define i index ;-)

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              • G gholamali Hosseini

                i am using 'i' and 'j' for iterating 2D arrays because 'i' and 'j' mean x and y in Cartesian coordinates. :) http://butterfly.blog.ir[^]

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                YDaoust
                wrote on last edited by
                #23

                Don't they mean 'horizontal' and 'vertical' ?

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                • P PIEBALDconsult

                  I was using i for index before I was introduced to Fortran.

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                  jsc42
                  wrote on last edited by
                  #24

                  If you were using 'i' before being introduced to FORTRAN, you must have been late being introduced. When I started, there was no lowercase! After some assemblers, FORTRAN IV (aka FORTRAN 66) was one of the first high level languages that I learnt and so I (like everybody else) used I, J, and K as loop variable names. I also used FORTRAN II at college. Shouldn't for(int i =0; i

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                  • Y YDaoust

                    Don't they mean 'horizontal' and 'vertical' ?

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                    gholamali Hosseini
                    wrote on last edited by
                    #25

                    maybe but I don't think so. horizontal -> h not 'i' & vertical ->v not 'j' the 'i' and 'j' are symbols for horizontal and vertical vectors.

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                    • G gholamali Hosseini

                      maybe but I don't think so. horizontal -> h not 'i' & vertical ->v not 'j' the 'i' and 'j' are symbols for horizontal and vertical vectors.

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                      YDaoust
                      wrote on last edited by
                      #26

                      probably i -> row and j -> column then

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                      • Y YDaoust

                        probably i -> row and j -> column then

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                        gholamali Hosseini
                        wrote on last edited by
                        #27

                        :omg: Hmmmmm...

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                        • B Brady Kelly

                          But I shudder to think why someone would venture right across the keyboard for a '1' instead of an 'i'. Yes, dataset.Tables[1] will work, but why, oh the humanity, why, are you not using the table name?

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                          Dan Neely
                          wrote on last edited by
                          #28

                          Brady Kelly wrote:

                          But I shudder to think why someone would venture right across the keyboard for a '1' instead of an 'i'.

                          Bad habits from the type writer era. http://www.flickr.com/photos/textlad/3564672292/[^]

                          Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies. -- Sarah Hoyt

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                          • T tumbledDown2earth

                            I am sure this was one of the hello-world codes for many of us ... But I wonder why the letter "i" .. I mean why on earth? With "a" the leading character why "i" ... After sometime I found out that Fortran language (which was/is historically used for scientific calculations) use "i" as a starting character for all integer type variables, and the quickest varible to write would be "i" Most authors and coders continued to use "i" even in C and then to C++ and then to C#, Java etc ... Is this an interpretation?

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                            WPerkins
                            wrote on last edited by
                            #29

                            I think you are right. If not otherwise defined FORTRAN would default to integer variables whose names started with "I" through "l" (ell) I believe. Not too sure about the ending letter as all *good* programmers defined their variables. After years of programming I still use "t" for temporary variables (like creating a value for the debugger to see) and "t.t" for file names for the same sort of thing - temporary names while developing. This comes from the old TRS80 system. Old habits die hard, eh?

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                            • T tumbledDown2earth

                              I am sure this was one of the hello-world codes for many of us ... But I wonder why the letter "i" .. I mean why on earth? With "a" the leading character why "i" ... After sometime I found out that Fortran language (which was/is historically used for scientific calculations) use "i" as a starting character for all integer type variables, and the quickest varible to write would be "i" Most authors and coders continued to use "i" even in C and then to C++ and then to C#, Java etc ... Is this an interpretation?

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                              fredrick72
                              wrote on last edited by
                              #30

                              I always use index and sometimes preppend it with the object or value i am indexing. It leads to a bit more verbose code but it is a hell of a lot easier to understand. Just my opinion.

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                              • T tumbledDown2earth

                                I am sure this was one of the hello-world codes for many of us ... But I wonder why the letter "i" .. I mean why on earth? With "a" the leading character why "i" ... After sometime I found out that Fortran language (which was/is historically used for scientific calculations) use "i" as a starting character for all integer type variables, and the quickest varible to write would be "i" Most authors and coders continued to use "i" even in C and then to C++ and then to C#, Java etc ... Is this an interpretation?

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                                mc42
                                wrote on last edited by
                                #31

                                Yes, it started in FORTRAN and leads to the following joke: God is real unless declared integer At least now you have the context so you can see the humor :)

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                                • W WPerkins

                                  I think you are right. If not otherwise defined FORTRAN would default to integer variables whose names started with "I" through "l" (ell) I believe. Not too sure about the ending letter as all *good* programmers defined their variables. After years of programming I still use "t" for temporary variables (like creating a value for the debugger to see) and "t.t" for file names for the same sort of thing - temporary names while developing. This comes from the old TRS80 system. Old habits die hard, eh?

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                                  tumbledDown2earth
                                  wrote on last edited by
                                  #32

                                  same thoughts

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                                  • M Matthew Bache

                                    If it wasn't for our coding standard, I would employ index, jndex... today. I like that idea.

                                    Matt

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                                    R Offline
                                    Rob Grainger
                                    wrote on last edited by
                                    #33

                                    Why not just skip to "spa"

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                                    • M mc42

                                      Yes, it started in FORTRAN and leads to the following joke: God is real unless declared integer At least now you have the context so you can see the humor :)

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                                      Rob Grainger
                                      wrote on last edited by
                                      #34

                                      Sorry, I still don't see the humour! (Sound of tumbleweed blowing)

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                                      • T tumbledDown2earth

                                        I am sure this was one of the hello-world codes for many of us ... But I wonder why the letter "i" .. I mean why on earth? With "a" the leading character why "i" ... After sometime I found out that Fortran language (which was/is historically used for scientific calculations) use "i" as a starting character for all integer type variables, and the quickest varible to write would be "i" Most authors and coders continued to use "i" even in C and then to C++ and then to C#, Java etc ... Is this an interpretation?

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                                        Michael A Cochran
                                        wrote on last edited by
                                        #35

                                        In my mind, it was because of FORTRAN. Back in the day, we didn't have all that many languages to choose from and most of us wrote in 360 assembler, FORTRAN, or COBOL. As others have said, while FORTRAN did have typing, variables starting with i-n were defaulted to integers so we just used i - followed by j, k, l in nested loops - for simplicity. We also used foo, foobar, and jane for "temp" variables. foo and foobar were common for IBM programmers and jane was common in DEC code.

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                                        • H H Brydon

                                          Look at any mathematics text that is older than computers. You will find i, j, k, m, n rampant as indexes for just about any formula you can find. Also, x, y, z are common variables and A, B, C are commonly used as constants.

                                          -- Harvey

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                                          englebart
                                          wrote on last edited by
                                          #36

                                          I second the math heritage. Remember the Capital Sigma sum sign like you see in Excel now? http://en.wikipedia.org/wiki/Summation#Capital-sigma_notation[^] PI is used for products. http://en.wikipedia.org/wiki/Multiplication#Capital_Pi_notation[^]

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