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Groups > comp.lang.c++ > #84048

Re: Implementing a two-way Turing Machine tape as an improvement to std::deque

From Mr Flibble <flibble@reddwarf.jmc>
Newsgroups comp.theory, comp.ai.philosophy, comp.lang.c, comp.lang.c++
Subject Re: Implementing a two-way Turing Machine tape as an improvement to std::deque
Message-ID <20220513002218.00003fa0@reddwarf.jmc> (permalink)
References <cNWdnXqV1cXzEuD_nZ2dnUU7_8zNnZ2d@giganews.com> <20220512235610.00004914@reddwarf.jmc> <Vf2dnR9fAewpDuD_nZ2dnUU7_8xh4p2d@giganews.com>
Organization Jupiter Mining Corp
Date 2022-05-13 00:22 +0100

Cross-posted to 4 groups.

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On Thu, 12 May 2022 18:09:39 -0500
olcott <NoOne@NoWhere.com> wrote:

> On 5/12/2022 5:56 PM, Mr Flibble wrote:
> > On Thu, 12 May 2022 17:51:25 -0500
> > olcott <NoOne@NoWhere.com> wrote:
> >   
> >> C/C++ people please critique this as the basis for an improvement
> >> to std::deque. It seems to have the key functionality of
> >> std::deque and does it much more simply while saving time and
> >> space. https://www.cplusplus.com/reference/deque/deque/
> >>
> >> #define tape_element unsigned char
> >>
> >> class Tape_Type
> >> {
> >> private:
> >>     int Tape_Head = 0;               // Can be negative
> >>     std::vector<tape_element> Left;  // Stores left expansion
> >>     std::vector<tape_element> Right; // Stores right expansion
> >>     tape_element & operator[](int index);
> >>
> >> public:
> >>     void move_left();      // Tape_Head--; Left.push_back(0); as
> >> needed void move_right();     // Tape_Head++; Left.push_back(0);
> >> as needed void Write(tape_element Y){ this->operator[](Tape_Head)
> >> = Y; }; tape_element Read()       { return
> >> this->operator[](Tape_Head); }; Tape_Type(){ Right.push_back('_');
> >> } // constructor void Output();
> >> };
> >>
> >> tape_element& Tape_Type::operator[](int index)
> >> {
> >>     if (index > 0)
> >>       return Right[index];
> >>     int Left_Index = ((index * -1) -1);
> >>     return Left[Left_Index];
> >> }
> >>
> >> void Tape_Type::Output()
> >> {
> >>     printf("Tape_Type::Output()\n");
> >>
> >>     if (Left.size())
> >>     {
> >>       int Last_One = Left.size() - 1;
> >>       for (int N = Last_One; N >= 0; N--)
> >>       {
> >>         int TH = (N + 1) * -1; // determine Tape_Head from N
> >>         printf("[%04d]:%c   Left[%02d]\n", TH, Left[N], N);
> >>       }
> >>     }
> >>     if (Right.size())
> >>       for (int N = 0; N < Right.size(); N++)
> >>         printf("[%04d]:%c  Right[%02d]\n", N, Right[N], N);
> >> }
> >>
> >> void Tape_Type::move_left()
> >> {
> >>     Tape_Head--;
> >>     int Left_Index = ((Tape_Head * -1) -1);
> >>     if (Left_Index == Left.size())
> >>       Left.push_back('_');
> >> }
> >>
> >> void Tape_Type::move_right()
> >> {
> >>     Tape_Head++;
> >>     if (Tape_Head == Right.size())
> >>       Right.push_back('_');
> >> }  
> > 
> > It might be a more appropriate solution than std::deque for your
> > specific use-case however it is NOT an improvement to std::deque for
> > the general case -- see my reply in the other thread for why.
> > 
> > /Flibble
> >   
> 
> I didn't see any reason why it would not make a better std::deque.
 
Because it doesn't meet the complexity and referential integrity
requirements of std::deque.

/Flibble

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Thread

Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 17:51 -0500
  Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-12 23:56 +0100
    Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 18:09 -0500
      Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 00:22 +0100
        Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 18:38 -0500
          Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 00:40 +0100
            Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 18:49 -0500
              Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 00:53 +0100
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 19:12 -0500
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 01:58 +0100
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 20:34 -0500
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Öö Tiib <ootiib@hot.ee> - 2022-05-12 21:05 -0700
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 08:02 +0100
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque tth <tth@none.invalid> - 2022-05-13 09:10 +0200
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-13 10:47 -0500
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Ben <ben.usenet@bsb.me.uk> - 2022-05-13 17:22 +0100
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Paavo Helde <eesnimi@osa.pri.ee> - 2022-05-13 19:31 +0300
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-13 10:58 -0500
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 17:02 +0100
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-05-13 12:44 -0700
  Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Richard Damon <Richard@Damon-Family.org> - 2022-05-12 19:23 -0400
    Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 18:32 -0500
  Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Ben <ben.usenet@bsb.me.uk> - 2022-05-13 01:06 +0100
    Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 19:55 -0500
      Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 02:01 +0100
        Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-12 20:36 -0500
          Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 08:04 +0100
            Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-13 11:00 -0500
              Re: Implementing a two-way Turing Machine tape as an improvement to std::deque Mr Flibble <flibble@reddwarf.jmc> - 2022-05-13 17:04 +0100
                Re: Implementing a two-way Turing Machine tape as an improvement to std::deque olcott <NoOne@NoWhere.com> - 2022-05-13 12:05 -0500

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