Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.lang.c Subject: Re: D correctly simulated by pure function H cannot possibly reach its, own line 06 Date: Sun, 26 May 2024 11:54:51 -0500 Organization: A noiseless patient Spider Lines: 41 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sun, 26 May 2024 18:54:51 +0200 (CEST) Injection-Info: dont-email.me; posting-host="b67ec24a85de95a55e6b4d0cc81926c3"; logging-data="3670723"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18aRhpRrqO9LkXANWwVfxx/" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:oxNabnX3LMbpBXx0h/2HHYWrv88= Content-Language: en-US In-Reply-To: Bytes: 2469 On 5/26/2024 11:04 AM, Mikko wrote: > On 2024-05-26 13:12:08 +0000, olcott said: >> I had to make the subject line of the thread a little less accurate >> so that people could get the gist of what I was saying. Now I have >> made it precise. > > Subject lines typically are as they are limited to one line. That's > not a problem. > *I finally have much better words* typedef int (*ptr)(); // ptr is pointer to int function in C 00 int H(ptr p, ptr i); 01 int D(ptr p) 02 { 03 int Halt_Status = H(p, p); 04 if (Halt_Status) 05 HERE: goto HERE; 06 return Halt_Status; 07 } 08 09 int main() 10 { 11 H(D,D); 12 return 0; 13 } When we see that D correctly simulated by pure simulator H would remain stuck in recursive simulation then we also know that D never reaches its own line 06 and halts in less than an infinite number of correctly simulated steps. This means that D correctly simulated by pure function H also never reaches it own line 06 and halts. -- Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer