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Re: initial size of a std::vector of std::strings

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Lynn McGuire <lynnmcguire5@gmail.com> writes:
> On 12/7/2022 3:49 PM, Keith Thompson wrote:
>> Lynn McGuire <lynnmcguire5@gmail.com> writes:
>> [...]
>>> I am trying to declare a vector with max_ncp strings in a struct.
>>> struct component_data {
>>> 	std::vector <std::string> component_names [max_ncp];
>>> 	doublereal heatoffusionatmeltingpoint [max_ncp];
>>> 	doublereal meltingpointtemperature [max_ncp];
>>> 	doublereal sublimationtemperature [max_ncp];
>>> 	doublereal triplepointtemperature [max_ncp];
>>> 	doublereal triplepointpressure [max_ncp];
>>> };
>>>
>>> Visual Studio 2015 does not like
>>>     	std::vector <std::string> component_names (max_ncp);
>>> or
>>> 	std::vector <std::string> component_names (max_ncp, "");
>> How does it express its dislike?  Both work for me:
>> #include <vector>
>> #include <string>
>> #include <iostream>
>> int main() {
>>      int max_ncp = 42;
>>      {
>>          std::vector<std::string> component_names(max_ncp);
>>          std::cout << component_names.size() << ' ';
>>      }
>>      {
>>          std::vector<std::string> component_names(max_ncp, "");
>>          std::cout << component_names.size() << '\n';
>>      }
>> }
>> The output is "42 42".
>> 
>>> But it does like
>>> 	std::vector <std::string> component_names [max_ncp];
>>> But it does not work.
>> That defines an array (not a std::array, just a C-style array
>> object) of
>> max_ncp vectors.  I think you want a single vector.
>> Do you want to set the initial size or the initial capacity?
>
> One vector with max_ncp strings in it.

So the initial state of the vector should be that it has a size() of
max_ncp, and each of the max_ncp strings it contains is initialized to
-- what, the empty string?

Then either this:
    std::vector<std::string> component_names(max_ncp);
or this:
    std::vector<std::string> component_names(max_ncp, "");
should give you want you want.  You said Visual Studio 2015 doesn't like
either of those, but you didn't say what it's complaint was.

Is the size of the vector going to change after it's been created?

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for XCOM Labs
void Void(void) { Void(); } /* The recursive call of the void */

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initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-06 23:42 -0600
  Re: initial size of a std::vector of std::strings James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-12-07 00:52 -0500
  Re: initial size of a std::vector of std::strings Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-07 08:17 +0100
  Re: initial size of a std::vector of std::strings Öö Tiib <ootiib@hot.ee> - 2022-12-07 00:23 -0800
    Re: initial size of a std::vector of std::strings Juha Nieminen <nospam@thanks.invalid> - 2022-12-07 09:13 +0000
      Re: initial size of a std::vector of std::strings Öö Tiib <ootiib@hot.ee> - 2022-12-07 06:03 -0800
        Re: initial size of a std::vector of std::strings Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-07 15:37 +0100
          Re: initial size of a std::vector of std::strings Öö Tiib <ootiib@hot.ee> - 2022-12-07 09:33 -0800
            Re: initial size of a std::vector of std::strings Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-07 18:45 +0100
      Re: initial size of a std::vector of std::strings Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-07 16:34 +0200
        Re: initial size of a std::vector of std::strings Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-07 15:38 +0100
        Re: initial size of a std::vector of std::strings Juha Nieminen <nospam@thanks.invalid> - 2022-12-08 07:58 +0000
    Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-07 16:28 -0600
      Re: initial size of a std::vector of std::strings Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-12-07 14:53 -0800
        Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-07 16:56 -0600
        Re: initial size of a std::vector of std::strings Juha Nieminen <nospam@thanks.invalid> - 2022-12-08 08:03 +0000
  Re: initial size of a std::vector of std::strings "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-12-07 12:28 +0100
    Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-07 14:54 -0600
      Re: initial size of a std::vector of std::strings "daniel...@gmail.com" <danielaparker@gmail.com> - 2022-12-07 13:16 -0800
      Re: initial size of a std::vector of std::strings "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-12-07 22:33 +0100
        Re: initial size of a std::vector of std::strings Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-07 22:37 +0100
      Re: initial size of a std::vector of std::strings Michael S <already5chosen@yahoo.com> - 2022-12-07 13:34 -0800
        Re: initial size of a std::vector of std::strings Bo Persson <bo@bo-persson.se> - 2022-12-07 23:48 +0100
      Re: initial size of a std::vector of std::strings Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-12-07 13:49 -0800
        Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-07 16:01 -0600
          Re: initial size of a std::vector of std::strings Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-12-07 14:47 -0800
            Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-07 17:09 -0600
      Re: initial size of a std::vector of std::strings Bo Persson <bo@bo-persson.se> - 2022-12-07 23:45 +0100
        Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-07 17:08 -0600
  Re: initial size of a std::vector of std::strings Lynn McGuire <lynnmcguire5@gmail.com> - 2022-12-08 01:44 -0600

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