Re: Why this does not compile on g++ but works in Visual C++ 2008

From:
"Alf P. Steinbach /Usenet" <alf.p.steinbach+usenet@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Sat, 10 Jul 2010 02:24:18 +0200
Message-ID:
<i18ejm$bnb$1@news.eternal-september.org>
* Jag, on 10.07.2010 01:25:

virtex<T>* add_a_virtex(const virtex<T>& v1) {
      //set<virtex<T> > _vertices ;
      pair<set<virtex<T> >::iterator,bool> itt = _vertices.insert(v1) ;
      /* code removed below */
}
on g++ I get this error.

sgraph.h: In member function `virtex<T>* sgraph<T>::add_a_virtex(const
virtex<T>&)':
sgraph.h:95: error: type/value mismatch at argument 1 in template
parameter list for `template<class _T1, class _T2> struct std::pair'
sgraph.h:95: error: expected a type, got `
std::set<virtex<T>,std::less<virtex<T> >,std::allocator<virtex<T> >

::iterator'

sgraph.h:95: error: invalid type in declaration before '=' token


You're probably missing a 'typename' keyword, like

   pair< typename virtex< T > >::iterator, bool > ...

If this is the problem, then T is a template parameter, and the compiler doesn't
absolutely know that virtex<T>::iterator is a type for all choices of T and
needs a little help from you about what it should assume.

This is in the FAQ somewhere, I believe.

Cheers & hth.,

- Alf

--
blog at <url: http://alfps.wordpress.com>

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