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Groups > comp.lang.c++ > #88435
| From | Bart <bc@freeuk.com> |
|---|---|
| Newsgroups | comp.lang.c, comp.lang.c++ |
| Subject | Re: Compute Unique Numbers in a Set |
| Date | 2023-01-08 14:48 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <tpel4n$ivd$1@gioia.aioe.org> (permalink) |
| References | <todbqe$16sg$1@gioia.aioe.org> <tpdas0$3oa34$1@dont-email.me> <tpdef6$2a759$1@news.xmission.com> <tpdfp6$3osch$1@dont-email.me> <tpdim3$3p3kb$1@dont-email.me> |
Cross-posted to 2 groups.
On 08/01/2023 05:01, Bonita Montero wrote:
> Now it's perfect:
>
> #include <iostream>
> #include <unordered_set>
> #include <charconv>
> #include <random>
>
> using namespace std;
>
> int main( int argc, char **argv )
> {
> try
> {
> if( argc < 4 )
> return
> cout << argv[0] << " n from to" << endl,
> EXIT_FAILURE;
> auto parse = []( char const *str, char const *err )
> {
> size_t value;
> if( from_chars_result fcr = from_chars( str, str + strlen(
> str ), value ); (bool)fcr.ec || *fcr.ptr )
> throw invalid_argument( err );
> return value;
> };
> size_t
> n = parse( argv[1], "wrong number of values" ),
> from = parse( argv[2], "wrong from-value" ),
> to = parse( argv[3], "wrong to-value" );
> if( from > to )
> swap( from, to );
> if( !n || n - 1 > to - from )
> return
> cout << "n is too small" << endl,
> EXIT_FAILURE;
> unordered_set<size_t> already;
> already.reserve( n );
> mt19937_64 mt;
> uniform_int_distribution<size_t> uid( from, to );
> while( already.size() != n )
> {
> size_t value;
> do
> value = uid( mt );
> while( already.contains( value ) );
> already.emplace( value );
> cout << value << endl;
> }
> }
> catch( exception const &exc )
> {
> return
> cout << exc.what() << endl,
> EXIT_FAILURE;
> }
> }
That's some torturous-looking code. My attempt for the same spec is give
below, in scripting code. Despite that, I'd argue that it would simpler
to use that as a starting point to create a C version rather than try
and adapt your C++ code, because it is basically pseudo-code.
Half of this is just reading and checking command line inputs which can
be in any manner at all. In any case it's of little relevance; of much
more use would be a function that returned a set of N unique random
numbers, that can be embedded into another program.
Note that your error message is wrong: N would be too large, not too small.
Neither version seeds the PRNG so they're both useless on repeated runs.
----------------------------------------------------------------
if ncmdparams<>3 then
println "Usage: N From To"
stop 1
fi
read n:"i", lower:"i", upper:"i"
if lower>upper then swap(lower,upper) fi
if n > upper-lower+1 then
abort("N is too large")
fi
a::=()
to n do
repeat
x:=random(lower..upper)
until x not in a
a &:= x
println x
od
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Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-08 06:01 +0100
Re: Compute Unique Numbers in a Set Bart <bc@freeuk.com> - 2023-01-08 14:48 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-08 18:22 +0100
Re: Compute Unique Numbers in a Set Bart <bc@freeuk.com> - 2023-01-08 17:46 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-09 04:58 +0100
Re: Compute Unique Numbers in a Set Bart <bc@freeuk.com> - 2023-01-09 11:26 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-09 15:57 +0100
Re: Compute Unique Numbers in a Set Bart <bc@freeuk.com> - 2023-01-08 17:34 +0000
Re: Compute Unique Numbers in a Set Ike Naar <ike@sdf.org> - 2023-01-08 21:45 +0000
Re: Compute Unique Numbers in a Set Bart <bc@freeuk.com> - 2023-01-08 23:13 +0000
Re: Compute Unique Numbers in a Set "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-01-08 15:18 -0800
Re: Compute Unique Numbers in a Set Tim Woodall <news001@woodall.me.uk> - 2023-01-13 06:35 +0000
Re: Compute Unique Numbers in a Set Tim Woodall <news001@woodall.me.uk> - 2023-01-13 06:39 +0000
Re: Compute Unique Numbers in a Set Paavo Helde <eesnimi@osa.pri.ee> - 2023-01-08 21:19 +0200
Re: Compute Unique Numbers in a Set Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-01-08 19:20 +0000
Re: Compute Unique Numbers in a Set "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-01-09 12:03 +0100
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-09 17:42 +0100
Re: Compute Unique Numbers in a Set Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-01-09 23:22 +0000
Re: Compute Unique Numbers in a Set Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-01-10 05:11 -0800
Re: Compute Unique Numbers in a Set Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-01-10 05:19 -0800
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-13 08:26 +0100
Re: Compute Unique Numbers in a Set Öö Tiib <ootiib@hot.ee> - 2023-01-13 03:26 -0800
Re: Compute Unique Numbers in a Set gazelle@shell.xmission.com (Kenny McCormack) - 2023-01-13 12:21 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-13 14:11 +0100
Re: Compute Unique Numbers in a Set gazelle@shell.xmission.com (Kenny McCormack) - 2023-01-13 13:55 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-13 15:02 +0100
Re: Compute Unique Numbers in a Set gazelle@shell.xmission.com (Kenny McCormack) - 2023-01-13 14:17 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-15 16:06 +0100
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-15 16:47 +0100
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-15 17:13 +0100
Re: Compute Unique Numbers in a Set Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-01-15 08:57 -0800
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-16 09:46 +0100
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-16 10:21 +0100
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-16 13:35 +0100
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-16 14:46 +0100
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-16 14:42 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-16 16:38 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-16 21:06 +0100
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-17 09:19 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-17 09:30 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-17 14:14 +0100
Re: Compute Unique Numbers in a Set Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-01-17 07:48 -0800
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-17 16:49 +0100
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-17 17:32 +0100
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-17 19:24 +0100
Re: Compute Unique Numbers in a Set Ralf Goertz <me@myprovider.invalid> - 2023-01-17 17:31 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-17 17:10 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-17 18:18 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-18 09:23 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-18 13:31 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-18 16:16 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-18 17:20 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-18 16:24 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-18 17:59 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-18 17:14 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-18 18:23 +0100
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-19 09:31 +0000
Re: Compute Unique Numbers in a Set "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-01-17 12:48 -0800
Re: Compute Unique Numbers in a Set scott@slp53.sl.home (Scott Lurndal) - 2023-01-17 21:21 +0000
Re: Compute Unique Numbers in a Set "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-01-17 13:29 -0800
Re: Compute Unique Numbers in a Set Paul N <gw7rib@aol.com> - 2023-01-18 06:50 -0800
Re: Compute Unique Numbers in a Set "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-01-18 11:59 -0800
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-17 16:25 +0000
Re: Compute Unique Numbers in a Set Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2023-01-17 09:08 -0800
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-17 17:16 +0000
Re: Compute Unique Numbers in a Set Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-01-17 17:32 +0000
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-18 09:23 +0000
Re: Compute Unique Numbers in a Set gazelle@shell.xmission.com (Kenny McCormack) - 2023-01-18 12:26 +0000
Re: Compute Unique Numbers in a Set Muttley@dastardlyhq.com - 2023-01-18 16:09 +0000
Re: Compute Unique Numbers in a Set Bart <bc@freeuk.com> - 2023-01-15 16:27 +0000
Re: Compute Unique Numbers in a Set Bonita Montero <Bonita.Montero@gmail.com> - 2023-01-15 17:42 +0100
Re: Compute Unique Numbers in a Set gazelle@shell.xmission.com (Kenny McCormack) - 2023-01-15 17:11 +0000
Re: Compute Unique Numbers in a Set Tim Woodall <news001@woodall.me.uk> - 2023-01-13 06:32 +0000
Re: Compute Unique Numbers in a Set Öö Tiib <ootiib@hot.ee> - 2023-01-13 05:04 -0800
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