From Newsgroup: comp.theory
On 10/9/2025 1:06 PM, Mr Flibble wrote:
Olcott admits that the Halting Problem is undecidable with the following words quoted verbatim:
DD is the caller of HHH(DD) that does the opposite of whatever HHH(DD)
reports. This makes it logically impossible for HHH to correctly report
on the behavior of its caller no matter what HHH does.
So if HHH is asked the question does my caller halt?
It is logically impossible for HHH to provide a correct answer.
/Flibble
You are a C programmer so you can get this.
Its fully operational code.
Only getch() is non-standard yet makes
the interface cleaner.
// As I first published here back in 2004:
// On 6/23/2004 9:34 PM, Olcott wrote:
#include <stdio.h>
#include <conio.h>
void LoopIfYouSayItHalts(bool YouSayItHalts)
{
if (YouSayItHalts)
while(true)
;
else
return;
}
void OutputProgram()
{
printf("\n\n\nvoid LoopIfYouSayItHalts "
"(bool YouSayItHalts)\n");
printf("{\n");
printf(" if (YouSayItHalts)\n");
printf(" while(true)\n");
printf(" ;\n");
printf(" else\n");
printf(" return;\n");
printf("}\n\n\n");
}
void Prompt()
{
char choice = 'x';
printf("Does this program Halt?\n");
printf("(Y or N) translated to Boolean argument"
" to LoopIfYouSayItHalts()\n");
printf("\nPlease ONLY PROVIDE CORRECT (Y or N) ANSWERS!\n");
while (choice != 'Y'&& choice != 'y' &&
choice != 'N' && choice != 'n')
{
choice = getch();
if (choice != 'Y'&& choice != 'y' &&
choice != 'N' && choice != 'n')
printf("Must be (Y or N)\n");
}
if (choice == 'Y' || choice == 'y')
{
printf("\nWrong Answer!\n"
"LoopIfYouSayItHalts(true) is stuck in a loop!\n\n");
LoopIfYouSayItHalts(true);
}
if (choice == 'N' || choice == 'n')
{
printf("\nWrong Answer!\n"
"LoopIfYouSayItHalts(false) halts now!\n\n");
LoopIfYouSayItHalts(false);
}
}
int main()
{
OutputProgram();
Prompt();
return 0;
}
--
Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer
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