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Groups > comp.lang.c++ > #82406
| From | Bonita Montero <Bonita.Montero@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: equal_range sucks ! |
| Date | 2021-11-23 17:13 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <snj401$dk6$1@dont-email.me> (permalink) |
| References | <snivjr$afv$1@dont-email.me> <snivuo$d2n$1@dont-email.me> |
Am 23.11.2021 um 16:04 schrieb Bonita Montero:
> Am 23.11.2021 um 15:59 schrieb Bonita Montero:
>> I just tried this:
>>
>> pair<cpu_it, cpu_it> foundApicId = equal_range( apicIds.begin(),
>> apicIds.end(),
>> apicId, []( cpu_apic_id const &idRange, unsigned apicId ) {
>> return idRange.apicId == apicId; } );
>>
>> It should be possible that the key for the range has a different type
>> than than the elemnens in the range so that I can compare against a
>> part of the range-objects like in the above code.
>>
>> Instead I'd hat to write:
>>
>> pair<cpu_it, cpu_it> foundApicId = equal_range( apicIds.begin(),
>> apicIds.end(),
>> cpu_apic_id( -1, apicId ), []( cpu_apic_id const &idRange,
>> cpu_apic_id const &id ) { return idRange.apicId == id.apicId; } );
>>
>
> And even more: I've to use const-references in my lambda.
> Who thinks up such nonsense ?
I've got it:
equal_range uses sth. lower_bound and upper_bound need < and >
comparison. This could be realized by swapping the parameters
on the predicate, therefore the predicate must be symmetrical.
A solution would be a predicate that returns a strong_ordering
object, so that no swapping would be necessary.
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equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 15:59 +0100
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 16:04 +0100
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 17:13 +0100
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 19:53 +0100
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-25 15:02 +0100
Re: equal_range sucks ! Juha Nieminen <nospam@thanks.invalid> - 2021-11-24 08:06 +0000
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-24 18:18 +0100
Re: equal_range sucks ! Marcel Mueller <news.5.maazl@spamgourmet.org> - 2021-11-28 12:36 +0100
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-28 17:04 +0100
Re: equal_range sucks ! Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-28 17:23 +0100
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