Re: Templating classes

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Fri, 1 Jun 2007 18:25:58 -0400
Message-ID:
<f3q6dn$1e4$1@news.datemas.de>
David C. wrote:

Also, 'std::vector<T>::iterator' is a dependent name. The compiler
doesn't know that it can be used where a type is expected. You need
to tell the compiler to trust you:

   for (typename std::vector<T>::iterator ...
        ^^^^^^^^


This is one of the reasons I like to use typedefs. It makes the code
easier to read and removes ambiguities. For example

   template<class T> class MatrixBase
   {
     protected:
       typedef std::vector<T> matrixrow_t;
       typedef std::vector<matrixrow_t> matrix_t;

       matrix_t matrix;
         ...

     public:
       void AddRow(const T &d = T())
       {
           for(matrix_t::iterator i = matrix.begin();


I believe you still have to use 'typename':

             for (typename matrix_t::iterator i = matrix.begin();

               i != matrix.end(); ++i)
           {
               i->push_back(d);
           }
           ++height;
       }
       ...
   };

[..]

-- David


V
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