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  • J Joel Bodenmann
    23 Jun 2016, 20:09

    The fact that container indexes start at zero is a language feature (I might be wrong?). Anyway, fact is that you can't just change it.
    What you can do is subclassing the container class and overloading the operator[] to add an offset. Note: That is a possible solution and not a recommendation.

    But as @Wieland already asked... Why would you want to do this?

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    Walux
    wrote on 24 Jun 2016, 00:38 last edited by
    #4

    @Joel-Bodenmann

    Thanks for your support , it's probably not the smoothest idea , but it's good enough .

    Taking things from beginning to end : That's my entertainment !

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    • ? A Former User
      23 Jun 2016, 19:54

      @Walux Why would you want to do this?

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      Walux
      wrote on 24 Jun 2016, 00:43 last edited by
      #5

      @Wieland

      Well , all i can say is that in my program i used a lot of QLists that are better off starting with 1 as an index , it would really make the work - and especially the code - more comfortable and readable .

      Taking things from beginning to end : That's my entertainment !

      K 1 Reply Last reply 24 Jun 2016, 10:28
      0
      • S Offline
        S Offline
        SGaist
        Lifetime Qt Champion
        wrote on 24 Jun 2016, 07:27 last edited by
        #6

        Hi,

        That's a pretty wrong idea. Your code is going to be understandable only by you and hard to debug for other people.

        All list/vector like containers are indexed at 0. You seem to try to work-around something else. What is it that makes your list related code "better off starting at 1" ?

        Interested in AI ? www.idiap.ch
        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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        • W Walux
          24 Jun 2016, 00:43

          @Wieland

          Well , all i can say is that in my program i used a lot of QLists that are better off starting with 1 as an index , it would really make the work - and especially the code - more comfortable and readable .

          K Offline
          K Offline
          kshegunov
          Moderators
          wrote on 24 Jun 2016, 10:28 last edited by
          #7

          @Walux

          are better off starting with 1 as an index

          This is what fortran does (and a few other obscure and useless languages) but it's arbitrary and completely artificial. An index in an array is the offset from the beginning of that array, so the first element has an offset of 0. There's no real, practical or good reason to think that arrays or lists should start from 1 just because people are used to counting that way; as I said such reasoning is arbitrary and is introduced completely artificially.

          Read and abide by the Qt Code of Conduct

          J 1 Reply Last reply 24 Jun 2016, 11:00
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          • K kshegunov
            24 Jun 2016, 10:28

            @Walux

            are better off starting with 1 as an index

            This is what fortran does (and a few other obscure and useless languages) but it's arbitrary and completely artificial. An index in an array is the offset from the beginning of that array, so the first element has an offset of 0. There's no real, practical or good reason to think that arrays or lists should start from 1 just because people are used to counting that way; as I said such reasoning is arbitrary and is introduced completely artificially.

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            jsulm
            Lifetime Qt Champion
            wrote on 24 Jun 2016, 11:00 last edited by
            #8

            @kshegunov Hey, I learned programming with Turbo Pascal (it's not obscure or useless for me :-)) where you can define whether first index is 0 or 1

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            K 1 Reply Last reply 24 Jun 2016, 11:11
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            • J jsulm
              24 Jun 2016, 11:00

              @kshegunov Hey, I learned programming with Turbo Pascal (it's not obscure or useless for me :-)) where you can define whether first index is 0 or 1

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              kshegunov
              Moderators
              wrote on 24 Jun 2016, 11:11 last edited by
              #9

              @jsulm
              Actually my beef is with fortran, but you're right of course ... ;)
              Still, C uses the zero-based (offset based) indexing and changing that would go against the language itself (not only against Qt) ... so there's no good reason to do (or even want) it.

              Read and abide by the Qt Code of Conduct

              J 1 Reply Last reply 24 Jun 2016, 11:13
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              • K kshegunov
                24 Jun 2016, 11:11

                @jsulm
                Actually my beef is with fortran, but you're right of course ... ;)
                Still, C uses the zero-based (offset based) indexing and changing that would go against the language itself (not only against Qt) ... so there's no good reason to do (or even want) it.

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                jsulm
                Lifetime Qt Champion
                wrote on 24 Jun 2016, 11:13 last edited by
                #10

                @kshegunov I agree with you: there is no need to redefine this behaviour.

                https://forum.qt.io/topic/113070/qt-code-of-conduct

                M J 2 Replies Last reply 24 Jun 2016, 12:52
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                • J jsulm
                  24 Jun 2016, 11:13

                  @kshegunov I agree with you: there is no need to redefine this behaviour.

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                  Joel Bodenmann
                  wrote on 24 Jun 2016, 13:31 last edited by Joel Bodenmann
                  #11

                  The "rest" of this topic got split into a separate topic.
                  Enjoy.

                  Industrial process automation software: https://simulton.com
                  Embedded Graphics & GUI library: https://ugfx.io

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                  • W Offline
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                    Walux
                    wrote on 24 Jun 2016, 13:48 last edited by Walux
                    #12

                    Thanks you all for your contribution :)

                    I think i'm now convinced that the QList's index must start with 0 , even tho that was not the goal of this topic :b

                    To help make the image clear , i used plenty of variables that MUST start with 1 , and these variables are connected to a lot of arrays , what i do now is create NULL variables and store them in the beginning of the arrays i wish to use its items from "1" .

                    For example :

                    int index0 = 0
                    QList<int> myArray;
                    myArray << index0 << myInteger1 << ...
                    
                    

                    But , is it safe all the time ?

                    Taking things from beginning to end : That's my entertainment !

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                    • S Offline
                      S Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on 24 Jun 2016, 13:50 last edited by
                      #13

                      Again: why must they start with 1 ?

                      A side effect of your current implementation is that you are wasting memory.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      W 1 Reply Last reply 24 Jun 2016, 13:53
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                      • S SGaist
                        24 Jun 2016, 13:50

                        Again: why must they start with 1 ?

                        A side effect of your current implementation is that you are wasting memory.

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                        Walux
                        wrote on 24 Jun 2016, 13:53 last edited by
                        #14

                        @SGaist

                        Hmmm , i guess that i should start accepting the way the arrays are built instead of making stubborn statements , thank you all for your advices .

                        I'll mark the topic as solved.

                        Taking things from beginning to end : That's my entertainment !

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                        • C Offline
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                          Chris Kawa
                          Lifetime Qt Champion
                          wrote on 24 Jun 2016, 19:00 last edited by
                          #15

                          To add to all the excellent points - stuffing an artificial null element just to try to index from 1 will break as soon as you do e.g. myArray.clear() or try to iterate with myArray.begin(), use a range based for or tons of other code types. c++ is 0 based language. Don't swim against the tide.

                          Btw. calling a QList myArray is like calling a sausage chain a nunchaku ;) Although similar at first glance they are completely different things. You'll mislead readers of your code. Don't do that.

                          W 1 Reply Last reply 25 Jun 2016, 00:19
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                          • C Chris Kawa
                            24 Jun 2016, 19:00

                            To add to all the excellent points - stuffing an artificial null element just to try to index from 1 will break as soon as you do e.g. myArray.clear() or try to iterate with myArray.begin(), use a range based for or tons of other code types. c++ is 0 based language. Don't swim against the tide.

                            Btw. calling a QList myArray is like calling a sausage chain a nunchaku ;) Although similar at first glance they are completely different things. You'll mislead readers of your code. Don't do that.

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                            W Offline
                            Walux
                            wrote on 25 Jun 2016, 00:19 last edited by
                            #16

                            @Chris-Kawa

                            Got it ;)

                            Taking things from beginning to end : That's my entertainment !

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