Re: templates in code

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Wed, 19 Mar 2008 10:02:00 -0400
Message-ID:
<frr6cp$41d$1@news.datemas.de>
Taras_96 wrote:

I found the following piece of code on the net and just wanted to
check whether I understood it correctly:

std::transform( s.begin(), s.end(), s.begin(),
std::bind1st( std::mem_fun( &std::ctype<char>::tolower ),
&std::use_facet< std::ctype<char> >( loc ) ) );

ctype<char>: is this implying that ctype is a templated class?


Yes.

so std::ctype<char>::tolower translates to:

the tolower member function of the ctype<char> class in the std name
space?


Yes.

also:

std::use_facet< std::ctype<char> >( loc )

it seems that the type of the return argument for use_facet has been
explicitly specified by <std::ctype<char> > - is this correct?


Yes.

Again,
is std::ctype<char> referencing a char instance of the ctype templated
class?


I don't think the expression "a char instance of" is idiomatic, but it
is not completely incomprehensible. And, again, yes.

It seems that this is correct when the definition of the use_facet
function is inspected:

   template <class Facet>
     Facet const& use_facet(locale const& loc);


I believe you've got it right.

V
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