Sujet : Re: Incorrect requirements --- Computing the mapping from the input to HHH(DD)
De : polcott333 (at) *nospam* gmail.com (olcott)
Groupes : comp.lang.cSuivi-à : comp.theoryDate : 09. May 2025, 03:58:40
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <vvjr10$2gaft$1@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
User-Agent : Mozilla Thunderbird
On 5/8/2025 9:23 PM, Keith Thompson wrote:
Richard Damon <richard@damon-family.org> writes:
On 5/8/25 7:53 PM, olcott wrote:
[...]
void DDD()
{
HHH(DDD);
return;
}
We don't need to look at any of my code for me
to totally prove my point. For example when
the above DDD is correctly simulated by HHH
this simulated DDD cannot possibly reach its own
"return" instruction.
>
And thus not correctly simulatd.
>
Sorry, there is no "OS Exemption" to correct simulaiton;.
Perhaps I've missed something. I don't see anything in the above that
implies that HHH does not correctly simulate DDD. Richard, you've read
far more of olcott's posts than I have, so perhaps you can clarify.
If we assume that HHH correctly simulates DDD, then the above code is
equivalent to:
void DDD()
{
DDD();
return;
}
which is a trivial case of infinite recursion. As far as I can tell,
assuming that DDD() is actually called at some point, neither the
outer execution of DDD nor the nested (simulated) execution of DDD
can reach the return statement. Infinite recursion might either
cause a stack overflow and a probable program crash, or an unending
loop if the compiler implements tail call optimization.
I see no contradiction, just an uninteresting case of infinite
recursion, something that's well understood by anyone with a
reasonable level of programming experience. (And it has nothing to
do with the halting problem as far as I can tell, though of course
olcott has discussed the halting problem elsewhere.)
Richard, what am I missing?
Now you are seeing what I was talking about.
Now you are seeing why I needed to cross post
to comp.lang.c
-- Copyright 2024 Olcott "Talent hits a target no one else can hit; Geniushits a target no one else can see." Arthur Schopenhauer