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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: Every sufficiently competent C programmer knows
Date: Wed, 12 Mar 2025 11:38:56 +0200
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On 2025-03-11 17:07:38 +0000, olcott said:

> On 3/11/2025 8:46 AM, Richard Heathfield wrote:
>> On 11/03/2025 13:31, olcott wrote:
>>> On 3/11/2025 5:28 AM, Mikko wrote:
>>>> On 2025-03-10 23:41:13 +0000, olcott said:
>>>> 
>>>>> typedef void (*ptr)();
>>>>> int HHH(ptr P);
>>>>> 
>>>>> void Infinite_Loop()
>>>>> {
>>>>>    HERE: goto HERE;
>>>>>    return;
>>>>> }
>>>>> 
>>>>> void Infinite_Recursion()
>>>>> {
>>>>>    Infinite_Recursion();
>>>>>    return;
>>>>> }
>>>>> 
>>>>> void DDD()
>>>>> {
>>>>>    HHH(DDD);
>>>>>    return;
>>>>> }
>>>>> 
>>>>> int DD()
>>>>> {
>>>>>    int Halt_Status = HHH(DD);
>>>>>    if (Halt_Status)
>>>>>      HERE: goto HERE;
>>>>>    return Halt_Status;
>>>>> }
>>>>> 
>>>>> That when HHH correctly emulates N steps of the
>>>>> above functions that none of these functions can
>>>>> possibly reach their own "return" instruction
>>>>> and terminate normally.
>>>> 
>>>> Every competent programmer knows that the information given is
>>>> insufficient to determine whether HHH emulates at all, and whether
>>>> it emulates correctly if it does.
>>>> 
>>>>> Since HHH does see that same pattern that competent
>>>>> C programmers see it correctly aborts its emulation
>>>>> and rejects these inputs as non terminating.
>>>> 
>>>> Whether HHH does see those patterns cannot be inferred from the information
>>>> given. Only about DDD one can see that it halts if HHH returns. In addition,
>>>> the given information does not tell whether HHH can see patterns that are
>>>> not there.
>>>> 
>>>> How many competent programmers you have asked?
>>> 
>>> Two C programmers with masters degrees in computer science
>>> agree that DDD correctly emulated by HHH cannot possibly
>>> reach its own "return" instruction and terminate normally.
>> 
>> Bring 'em on. Perhaps /they/ have the source to HHH, because without it 
>> you don't have anything. (And btw whatever it is you claim to have is 
>> far from clear, because all I've seen so far is an attempt to express 
>> the Halting Problem in C and pseuodocode, where the pseudocode reads: 
>> HHH(){ magic happens }
> 
> You still sound like Richard Damon whom is unable to
> understand that semantic tautologies are irrefutable.

That a false claim about one person is similar to a false claim about
another is not suffecent ro conclude or even sustpect that they are
the same. A better measure is how meny indignificant typos each makes.

> When N steps of the above the above functions are
> correctly emulated by HHH
> (this is all that you need to know able HHH) then
> none of them reach their "return" instruction and
> terminate normally.
> 
> HHH can and does emulate itself emulating DDD and DD.

Not completely. Not to the point where the emulated HHH returns.

-- 
Mikko