Re: Code specific to couples of classes
On 7 Mar, 09:55, "Grizlyk" <grizl...@yandex.ru> wrote:
Gavin Deane wrote:
Alan Johnson wrote:
If you want some authoritative word on that try Item 23 of Scott
Meyer's Effective C++: "Prefer non-member non-friend functions
to member functions."
I do not know what Scott Meyer meant but think, it is not general
rule.
Member function can have encapsulated data so member function can be
better than plain function.
He meant this
http://www.ddj.com/dept/cpp/184401197
1.
He has written: "It's important that we're trying to choose between
member
functions and non-friend non-member functions".
As i can understand "non-friend non-member function" is a function, th=
at
can
use only public interface of the class.
No. A non-member non-friend *is part of* the interface. It operates on
objects through the public member functions, which are another part of
the interface. The whole point of that article is that it is a mistake
to think that public member functions are the only thing that make up
a class's interface.
It is standard OO convention "to thing that class's interface is only cla=
ss
members". We can speak about namespace as a kind of opened interface, abo=
ut
two classes, representing solid interface and so on, but there are other
things, another terms, not "class's interface".
Well, my dictionary says that the verb "interface" means to interact.
So an interface of an object is the means with which we interact with
the object, be they member methods or not.
You can always be a purist and stick to some definition made by
someone sometime, but for the rest of the world a notation, such as
OO, changes over time (just as the meaning of words in natural
language) as new ways and uses are discovered. Personally I think it's
a good idea to include non-friend non-member functions in the
interface sine it makes a lot of classes more useful. Just look at
std::vector, it's a sequential container in which you can put/access/
remove thing and not much more. But if you add all the functionality
from <algorithms> it's suddenly a lot more useful.
--
Erik Wikstr=F6m