Re: What's wrong with this code?

From:
"Alf P. Steinbach" <alfps@start.no>
Newsgroups:
comp.lang.c++
Date:
Fri, 04 Apr 2008 20:22:50 +0200
Message-ID:
<ga6dncXs55AR7GvanZ2dnUVZ_qainZ2d@comnet>
* Kelvin Moss:

On Apr 4, 10:42 am, Rolf Magnus <ramag...@t-online.de> wrote:

Kelvin Moss wrote:

struct Person {
    string name;
    int age;
    Person(string n, int i):name(n), age(i)
    {}
Comeau cribs like --
"sequence_concepts.h", line 31: error: no instance of constructor
          "Person::Person" matches the argument list
      typename _XX::value_type __t = typename _XX::value_type();
May be I am missing something?

Yes. You are missing a default constructor.


Yes, that fixes the problem.

The compiler only generates one if you don't have user-defined constructors
in your class.


I know this thing. So I need the default constructor because of STL
requirements? I know this might be compiler specific but can you tell
me where default construction might be taking place here?


As far as I can recall, Comeau is wrong here. The container element type needs
to be copy constructable and assignable (and, curiously, not redefine the
address operator to yield anything but the object's address), but that's it, as
far as I can recall.

Maybe someone can check the standard (I'm not in the mood).

But it sure looks like Comeau is very very wrong.

Cheers, & hth.,

- Alf

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