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Groups > comp.lang.c++ > #72257

Re: overuse of auto is dangerous

From jacobnavia <jacob@jacob.remcomp.fr>
Newsgroups comp.lang.c++
Subject Re: overuse of auto is dangerous
Date 2020-03-13 08:51 +0100
Organization A noiseless patient Spider
Message-ID <r4fe24$bcm$1@dont-email.me> (permalink)
References <r4eghj$j17$1@dont-email.me> <hd08qjFilvfU1@mid.individual.net>

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Le 13/03/2020 à 03:17, Bo Persson a écrit :
> On 2020-03-13 at 00:27, jacobnavia wrote:
>> Consider:
>>
>> auto f = foo();
>>
>> What is "f"?
> 
> Easy, "f" is the return value of foo(). Probably some kind of iterator 
> that you are just going to pass to one or more std::algorithm, so you 
> don't really care to spell out its name.
> 
> 
>>
>> Ahhh you have to figure out the return type of foo() of course. Great, 
>> there you go to your favorite IDE and try to jump to the correct 
>> definition of the foo() method in the correct class with the correct 
>> overload resolution...
>>
>> Even worst... when you change the return type of foo() from type A to 
>> type Z, all the "auto" constructs will continue to compile 
>> AUTOmatically of course. Problem is, the type of "f" will have changed 
>> and that can provoke incomprehensible compile time errors further down 
>> or even run time errors in the form of access violation or whatever!
>>
>> Wouldn't it be better to write:
>>
>> TYPE_A F = foo();
> 
> 
> You mean like
> 
> typename std::unordered_map<key, data, std::hash<key>, 
> std::equal_to<key>, special_allocator<std::pair<const key, 
> data>>>::const_iterator F = foo();
> 

Well, I know that C++ can be very unreadable. Maintaining C++ can be a 
nightmare, but yes, I would prefer that long declaration since I know 
that at the end f should be a const_iterator (if I parsed that correctly 
from the template forest there).

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overuse of auto is dangerous jacobnavia <jacob@jacob.remcomp.fr> - 2020-03-13 00:27 +0100
  Re: overuse of auto is dangerous Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-03-13 00:27 +0000
  Re: overuse of auto is dangerous Ian Collins <ian-news@hotmail.com> - 2020-03-13 13:57 +1300
    Re: overuse of auto is dangerous Daniel <danielaparker@gmail.com> - 2020-03-12 18:16 -0700
      Re: overuse of auto is dangerous Ian Collins <ian-news@hotmail.com> - 2020-03-13 16:17 +1300
        Re: overuse of auto is dangerous Daniel <danielaparker@gmail.com> - 2020-03-12 20:48 -0700
          Re: overuse of auto is dangerous "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2020-03-13 21:27 +0100
            Re: overuse of auto is dangerous Daniel <danielaparker@gmail.com> - 2020-03-13 13:35 -0700
  Re: overuse of auto is dangerous Cholo Lennon <chololennon@hotmail.com> - 2020-03-12 22:06 -0300
  Re: overuse of auto is dangerous Bo Persson <bo@bo-persson.se> - 2020-03-13 03:17 +0100
    Re: overuse of auto is dangerous jacobnavia <jacob@jacob.remcomp.fr> - 2020-03-13 08:51 +0100
    Re: overuse of auto is dangerous Öö Tiib <ootiib@hot.ee> - 2020-03-13 01:14 -0700
      Re: overuse of auto is dangerous Vir Campestris <vir.campestris@invalid.invalid> - 2020-03-16 21:35 +0000
        Re: overuse of auto is dangerous Ian Collins <ian-news@hotmail.com> - 2020-03-17 11:49 +1300
    Re: overuse of auto is dangerous Bonita Montero <Bonita.Montero@gmail.com> - 2020-03-13 21:27 +0100
  Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-13 11:07 +0100
    Re: overuse of auto is dangerous Bart <bc@freeuk.com> - 2020-03-13 10:39 +0000
      Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-13 14:26 +0100
        Re: overuse of auto is dangerous jacobnavia <jacob@jacob.remcomp.fr> - 2020-03-14 09:20 +0100
          Re: overuse of auto is dangerous Sam <sam@email-scan.com> - 2020-03-14 10:12 -0400
          Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-14 16:12 +0100
            Re: overuse of auto is dangerous Bart <bc@freeuk.com> - 2020-03-14 17:23 +0000
              Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-15 12:27 +0100
                Re: overuse of auto is dangerous Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-03-15 15:41 -0700
                Re: overuse of auto is dangerous Ian Collins <ian-news@hotmail.com> - 2020-03-16 13:37 +1300
                Re: overuse of auto is dangerous Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-03-16 07:26 +0000
                Re: overuse of auto is dangerous Sam <sam@email-scan.com> - 2020-03-16 07:05 -0400
                Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-16 12:32 +0100
                Re: overuse of auto is dangerous Sam <sam@email-scan.com> - 2020-03-16 08:21 -0400
                Re: overuse of auto is dangerous Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-03-16 11:27 +0000
                Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-16 09:11 +0100
                Re: overuse of auto is dangerous Bart <bc@freeuk.com> - 2020-03-16 11:44 +0000
                Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-03-16 13:29 +0100
                Re: overuse of auto is dangerous Öö Tiib <ootiib@hot.ee> - 2020-03-16 05:35 -0700
                Re: overuse of auto is dangerous James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-03-16 09:16 -0400
                Re: overuse of auto is dangerous Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 07:13 -0700
                Re: overuse of auto is dangerous James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-02 07:45 -0700
                Re: overuse of auto is dangerous Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-02 10:25 -0700
                Re: overuse of auto is dangerous Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-04 12:49 -0700
                Re: overuse of auto is dangerous David Brown <david.brown@hesbynett.no> - 2020-04-05 14:15 +0200
                Re: overuse of auto is dangerous Paavo Helde <myfirstname@osa.pri.ee> - 2020-04-02 19:20 +0300
                Re: overuse of auto is dangerous Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-04-02 10:19 -0700
        Re: overuse of auto is dangerous Bonita Montero <Bonita.Montero@gmail.com> - 2020-03-15 16:26 +0100
    Re: overuse of auto is dangerous Daniel <danielaparker@gmail.com> - 2020-03-13 07:27 -0700
      Re: overuse of auto is dangerous Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-03-13 21:22 +0000
      Re: overuse of auto is dangerous Melzzzzz <Melzzzzz@zzzzz.com> - 2020-03-14 04:53 +0000
        Re: overuse of auto is dangerous Öö Tiib <ootiib@hot.ee> - 2020-03-14 03:23 -0700
          Re: overuse of auto is dangerous Melzzzzz <Melzzzzz@zzzzz.com> - 2020-03-14 13:20 +0000
            Re: overuse of auto is dangerous Öö Tiib <ootiib@hot.ee> - 2020-03-14 09:20 -0700
  Re: overuse of auto is dangerous Paavo Helde <myfirstname@osa.pri.ee> - 2020-03-13 13:53 +0200
  Re: overuse of auto is dangerous Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2020-03-13 15:46 +0000
  Re: overuse of auto is dangerous Sam <sam@email-scan.com> - 2020-03-13 23:09 -0400
  Re: overuse of auto is dangerous Bonita Montero <Bonita.Montero@gmail.com> - 2020-03-14 08:06 +0100
    Re: overuse of auto is dangerous Melzzzzz <Melzzzzz@zzzzz.com> - 2020-03-14 13:16 +0000
      Re: overuse of auto is dangerous Bonita Montero <Bonita.Montero@gmail.com> - 2020-03-16 15:31 +0100

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