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From: olcott <polcott333@gmail.com>
Newsgroups: comp.lang.c,comp.lang.c++
Subject: Re: Can D correctly simulated by H reach its own line 06 and halt?
Date: Wed, 22 May 2024 08:53:41 -0500
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On 5/22/2024 6:50 AM, Bonita Montero wrote:
> Am 22.05.2024 um 13:01 schrieb Sam:
>> olcott writes:
>>
>>>> Unfortunately, all our psychics are out to lunch and there's noone 
>>>> in the office who knows how to operate the magical mind ray-beam 
>>>> machine that's needed in order to extract all the relevant details 
>>>> from your head. You'll need to patiently wait until the lunch break 
>>>> is over.
>>>>
>>>> We apologize for the inconvenience.
>>>>
>>>
>>> typedef int (*ptr)();  // ptr is pointer to int function in C
>>
>> You're stuck in an infinite loop. Try pressing CTRL-ALT-DEL. This will 
>> break you out of your infinite loop.
> 
> I think he is stuck in a mental infinite loop.
> 
>>
>> Then, it's time to figure out how to fix your infinite loop. You need 
>> to attach a debugger. I saw Jerry do this once to Tom, by sticking 
>> Tom's tail into a socket. You don't have a tail. But you have hands. 
>> With plenty of fingers. You only need two (don't worry about the 
>> ground plug). Your fingers are probably too thick to fit. You need a 
>> pair of forks.


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       }

It is trivial to see that for every H/D pair of the infinite
set of H/D pairs that match the above template that

D correctly simulated by H cannot possibly reach its own final
state at line 06 and halt because D correctly simulated by
H remains stuck in recursive simulation.

This provides the basis for simulating termination analyzer H to
correctly determine that the halting problem's counter-example
input D cannot possibly halt.


-- 
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer