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Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: wij <wyniijj5@gmail.com> Newsgroups: comp.theory Subject: Re: Every sufficiently competent C programmer knows Date: Wed, 12 Mar 2025 02:33:15 +0800 Organization: A noiseless patient Spider Lines: 49 Message-ID: <a3304ec1dc4a774e1570a5bcaee4732327635974.camel@gmail.com> References: <vqntaq$1jut5$1@dont-email.me> <vqp388$1tvqa$1@dont-email.me> <vqpdv9$202b2$2@dont-email.me> <vqperb$20c9k$2@dont-email.me> <E6mcnWv3nMa66036nZ2dnZfqnPWdnZ2d@brightview.co.uk> <vqpv2u$23vhr$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Injection-Date: Tue, 11 Mar 2025 19:33:16 +0100 (CET) Injection-Info: dont-email.me; posting-host="920c9e6d430639ea994965ae553fae8b"; logging-data="2210526"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19A14DrrbO1FcMFv8paeQ3p" User-Agent: Evolution 3.54.3 (3.54.3-1.fc41) Cancel-Lock: sha1:2ElDZjrxc10HkeIusZ2w2E61VCs= In-Reply-To: <vqpv2u$23vhr$1@dont-email.me> Bytes: 2719 On Tue, 2025-03-11 at 18:23 +0000, Richard Heathfield wrote: > On 11/03/2025 17:42, Mike Terry wrote: > > Finally, if you really want to see the actual HHH code, its in=20 > > the halt7.c file (along with DDD) that PO provides links to from=20 > > time to time.=C2=A0 However it's not very illuminating due to=20 > > bugs/design errors/misunderstandings which only serve to=20 > > obfuscate PO's errors in thinking. >=20 > [I've now seen the code. Oh deary deary me.] >=20 > Thank you for a spirited attempt to be cogent - or at least as=20 > cogent as it is possible to be in the circumstances! >=20 > I think PO's first step must be to demonstrate that HHH()=20 > correctly diagnoses some easy functions, such as these: >=20 > int rha(unsigned int i) > { > =C2=A0=C2=A0 while(--i > 0)while(--i > 0); > =C2=A0=C2=A0 return 0; > } >=20 > int rhb(unsigned int i) > { > =C2=A0=C2=A0 if(i > 0) > =C2=A0=C2=A0 { > =C2=A0=C2=A0=C2=A0=C2=A0 rhb(i/10); > =C2=A0=C2=A0 } > =C2=A0=C2=A0 return putchar(i + '0'); > } >=20 > int rhc(unsigned int i) > { > =C2=A0=C2=A0 typedef int(*pf)(unsigned int); > =C2=A0=C2=A0 pf arr[3] =3D {rha, rhb, rhc}; > =C2=A0=C2=A0 return arr[i % 3]; > } >=20 > and other such obvious tests. >=20 > HHH(), the procedure that decides whether a program halts, is=20 > required to work for all programs and all inputs. Does it work on=20 > those cited above? I'm guessing it doesn't. >=20 No TM can simulate itself. Proving HP in this way is dead end.