Re: DDD simulated by HHH cannot possibly halt (Halting Problem)

On 04/04/2025 05:08, olcott wrote:

On 4/3/2025 9:58 PM, Richard Heathfield wrote:

[Post in comp.lang.c, read in comp.lang.c]
>
On 04/04/2025 03:45, olcott wrote:

On 4/3/2025 9:39 PM, Richard Heathfield wrote:

[Post in comp.lang.c, read in comp.lang.c]
>
On 04/04/2025 02:27, olcott wrote:

void DDD()
{
    HHH(DDD);
    return;
}
>
Do you really think that anyone knowing the C
programming language is too stupid to see that
DDD simulated by HHH cannot possibly return?

>
Anyone knowing the C language will know on seeing your code that

>
I am correct

>
Oh, I see. Yes, of course you are. Well done.
>
"DDD simulated by HHH cannot possibly return".
>
Then HHH cannot possibly simulate DDD.
>

everything else is off-topic for this post.

>
And HHH() is off-topic for this newsgroup. You started the thread in comp.lang.c, so to make it topical you'd have to rewrite HHH() in C instead of peppering your code with assembly language calls.
>

 The halting problem in C would seem to be relevant to C groups

The C code would be topical, yes. [Note that comp.lang.c++ is not a C group. It's a C++ group.] But the assembly language calls are not topical here.

typedef void (*ptr)();
int HHH(ptr P);
  int DD()
{
   int Halt_Status = HHH(DD);
   if (Halt_Status)
     HERE: goto HERE;
   return Halt_Status;
}
 int main()
{
   HHH(DD);
}
 DD simulated by HHH gets stuck on its first line.

Then HHH is failing to correctly analyse DD for determining whether it halts, and therefore it is failing to address the Halting Problem.
Non-working simulations are a dime a dozen, and they prove nothing.
--
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
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