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From: DFS <nospam@dfs.com>
Newsgroups: comp.lang.c
Subject: Re: Suggested method for returning a string from a C program?
Date: Wed, 19 Mar 2025 13:23:47 -0400
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On 3/19/2025 5:55 AM, Michael S wrote:
> On Wed, 19 Mar 2025 00:38:44 -0400
> DFS <nospam@dfs.com> wrote:
> 
>> On 3/18/2025 11:07 PM, Tim Rentsch wrote:
>>
>>
>>> Have you thought about how large the value of 'n' can
>>> become inside the while() loop?
>>
>> I was too smug in my first reply.  After Keith pointed out I needed
>> to read from stdin, I submitted the code again and it passed some
>> tests but failed with 'OUTPUT LIMIT EXCEEDED' when n = 159487.
>>
>> Updating int to long worked, and now I'm bona fide!
>>
>> So thanks.
> 
> What you did happens to be sufficient for a particular environment
> (supposedly, x86-64 Linux) used both by yourself and by the server that
> tests results.
> In more general case, 'long' is not guaranteed to handle numbers in
> range up to 18,997,161,173 that can happen in this test.

How did you determine that?

I ran the program for inputs 1 to 10^6 (1 million):

Windows11, Tiny C compiler
$ ptime weird 1 1000000
max n = 56991483520 reached at input = 704511
Execution time: 0.559 s

Kali Linux (Windows WSL), gcc
$ time ./weird 1 1000000
max n = 56991483520 reached at input = 704511
real    0m0.330s

(56,991,483,520)



> Something like int64_t would be safer.

Indeed.  My code bombed using long when the input n = 151177.

Used int64_t and it didn't bomb.


Thanks