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  3. The History of "i" [modified]

The History of "i" [modified]

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  • A alex barylski

    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

    Steve EcholsS Offline
    Steve EcholsS Offline
    Steve Echols
    wrote on last edited by
    #10

    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!

    • S
      50 cups of coffee and you know it's on!
      Code, follow, or get out of the way.
    1 Reply Last reply
    0
    • A alex barylski

      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

      R Offline
      R Offline
      Roger Wright
      wrote on last edited by
      #11

      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

      Steve EcholsS J 2 Replies Last reply
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      • R Roger Wright

        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

        Steve EcholsS Offline
        Steve EcholsS Offline
        Steve Echols
        wrote on last edited by
        #12

        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!

        • S
          50 cups of coffee and you know it's on!
          Code, follow, or get out of the way.
        1 Reply Last reply
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        • V Vikram A Punathambekar

          What do you mean by "the times there was no i"? :~ Cheers, Vikram.


          I don't know and you don't either. Militant Agnostic

          R Offline
          R Offline
          Ryan Binns
          wrote on last edited by
          #13

          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"

          M 1 Reply Last reply
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          • A alex barylski

            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

            R Offline
            R Offline
            Rage
            wrote on last edited by
            #14

            it is only "i" like "i"nteger, or "s" like "s"tring. ~RaGE();

            Steve EcholsS 1 Reply Last reply
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            • R Ryan Binns

              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"

              M Offline
              M Offline
              MatthysDT
              wrote on last edited by
              #15

              How does one discover a letter? :laugh::confused:

              D L 2 Replies Last reply
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              • C Christian Graus

                I thought i/j/k were commonly used in mathematical circles, and so they just moved in to code. Christian Graus - Microsoft MVP - C++

                C Offline
                C Offline
                Chris Maunder
                wrote on last edited by
                #16

                i is reserved for sqrt(-1) cheers, Chris Maunder

                CodeProject.com : C++ MVP

                D C F R 4 Replies Last reply
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                • R Rage

                  it is only "i" like "i"nteger, or "s" like "s"tring. ~RaGE();

                  Steve EcholsS Offline
                  Steve EcholsS Offline
                  Steve Echols
                  wrote on last edited by
                  #17

                  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!

                  • S
                    50 cups of coffee and you know it's on!
                    Code, follow, or get out of the way.
                  R 1 Reply Last reply
                  0
                  • C Chris Maunder

                    i is reserved for sqrt(-1) cheers, Chris Maunder

                    CodeProject.com : C++ MVP

                    D Offline
                    D Offline
                    David Stone
                    wrote on last edited by
                    #18

                    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

                    R C P 3 Replies Last reply
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                    • M MatthysDT

                      How does one discover a letter? :laugh::confused:

                      D Offline
                      D Offline
                      David Stone
                      wrote on last edited by
                      #19

                      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

                      R 1 Reply Last reply
                      0
                      • D David Stone

                        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

                        R Offline
                        R Offline
                        Ryan Binns
                        wrote on last edited by
                        #20

                        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"

                        L 1 Reply Last reply
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                        • Steve EcholsS Steve Echols

                          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!

                          R Offline
                          R Offline
                          Ryan Binns
                          wrote on last edited by
                          #21

                          Steve Echols wrote:

                          I'm not a camel either

                          :laugh: Are you sure?

                          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"

                          Steve EcholsS 1 Reply Last reply
                          0
                          • D David Stone

                            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

                            R Offline
                            R Offline
                            Ryan Binns
                            wrote on last edited by
                            #22

                            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"

                            1 Reply Last reply
                            0
                            • R Ryan Binns

                              Steve Echols wrote:

                              I'm not a camel either

                              :laugh: Are you sure?

                              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"

                              Steve EcholsS Offline
                              Steve EcholsS Offline
                              Steve Echols
                              wrote on last edited by
                              #23

                              :laugh: No humps! Just double checked. Although...hunching over my monitor might give me a "single" in a couple more years. :)


                              - S 50 cups of coffee and you know it's on!

                              • S
                                50 cups of coffee and you know it's on!
                                Code, follow, or get out of the way.
                              L 1 Reply Last reply
                              0
                              • D David Stone

                                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

                                C Offline
                                C Offline
                                code frog 0
                                wrote on last edited by
                                #24

                                Quit being irrational!:laugh:


                                The enemy's gate is down. :cool: Welcome to CP in your language. Post the unicode version in My CP Blog[^] now.

                                K 1 Reply Last reply
                                0
                                • M Mircea Grelus

                                  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.

                                  H Offline
                                  H Offline
                                  Henrik Husted
                                  wrote on last edited by
                                  #25

                                  So you also programmed on ZX Spectrum :)

                                  M 1 Reply Last reply
                                  0
                                  • C code frog 0

                                    Quit being irrational!:laugh:


                                    The enemy's gate is down. :cool: Welcome to CP in your language. Post the unicode version in My CP Blog[^] now.

                                    K Offline
                                    K Offline
                                    KaRl
                                    wrote on last edited by
                                    #26

                                    Yep, it is beginning to become complex :)


                                    Pull the tapeworm out of your ass Fold with us! ¤ flickr

                                    C 1 Reply Last reply
                                    0
                                    • K KaRl

                                      Yep, it is beginning to become complex :)


                                      Pull the tapeworm out of your ass Fold with us! ¤ flickr

                                      C Offline
                                      C Offline
                                      code frog 0
                                      wrote on last edited by
                                      #27

                                      The possibilities are transcendental when you get David and Ryan going on Mathematics. Add in Chris and well... somehow it all equals "i" in the end...:laugh:


                                      The enemy's gate is down. :cool: Welcome to CP in your language. Post the unicode version in My CP Blog[^] now.

                                      C 1 Reply Last reply
                                      0
                                      • C Chris Maunder

                                        i is reserved for sqrt(-1) cheers, Chris Maunder

                                        CodeProject.com : C++ MVP

                                        C Offline
                                        C Offline
                                        code frog 0
                                        wrote on last edited by
                                        #28

                                        I think I reserved i for 2 people at 7:00. :doh:


                                        The enemy's gate is down. :cool: Welcome to CP in your language. Post the unicode version in My CP Blog[^] now.

                                        D 1 Reply Last reply
                                        0
                                        • A alex barylski

                                          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

                                          A Offline
                                          A Offline
                                          Andrew Torrance
                                          wrote on last edited by
                                          #29

                                          ok , but why no f in cake ?

                                          1 Reply Last reply
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