Path: csiph.com!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: Suggested method for returning a string from a C program? Date: Thu, 20 Mar 2025 04:59:11 -0700 Organization: A noiseless patient Spider Lines: 45 Message-ID: <86v7s3oquo.fsf@linuxsc.com> References: <86frj8pyme.fsf@linuxsc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Thu, 20 Mar 2025 12:59:15 +0100 (CET) Injection-Info: dont-email.me; posting-host="7c01e97b5d1836204810413d59dbf156"; logging-data="3257331"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+9smh/BGBcp4FXve1Y/WShgKjVJH2F4Ws=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:yqw56YKgN11z5sI4e3yMw/Gh8gM= sha1:lHtViz17/+7yEhNQ52YIMZoqnxs= Xref: csiph.com comp.lang.c:391393 Muttley@DastardlyHQ.org writes: > On Wed, 19 Mar 2025 13:13:45 -0700 > Tim Rentsch wibbled: > >> Muttley@DastardlyHQ.org writes: >> >>> On Wed, 19 Mar 2025 09:03:33 -0400 >>> DFS wibbled: >>> >>>> On 3/19/2025 6:15 AM, bart wrote: >>>> >>>>> On 19/03/2025 01:38, DFS wrote: >>>>> >>>>>> I'm doing these algorithm problems at >>>>>> https://cses.fi/problemset/list/ >>>>>> >>>>>> For instance: Weird Algorithm >>>>>> https://cses.fi/problemset/task/1068 >>>>> >>>>> This is related to the Collatz Conjecture. What's weird is not >>>>> mentioning it. >>>> >>>> I wouldn't have known it was a famous math conjecture, but no >>>> doubt the author of the problem did. >>> >>> Reading wikipedia it looks like one of those dull problems >>> mathematicians think up when they've got too much free time on >>> their hands. >> >> The 3n+1 problem, as it is sometimes called, is interesting >> because it is easy to state and easy to understand, even without >> any mathematical training beyond grade school, and yet has >> resisted the efforts of many of the best mathematicians in the >> world to try to prove it. It seems like it should be easy, but >> it is in fact incredibly difficult, based on almost 100 years of >> experience. > > I guess some maths problems can't be proven directly, they have to > be - for want of a better word - run. A bit like the halting > problem in CS. Indeed it is the case that some statements are not provable, even though they may still be true. But the 3n+1 problem is unlikely to be in that category; it is just very hard to prove.