CGAL users discussion list

[Ross Hemsley <>]

I am writing a class with a series of functions that work by applying

functors to an iterator range over a set of elements.

Example:

template< typename Iterator, typename Functor >

double mean(Iterator begin, Iterator end, Functor f)

{

    double sum   = 0;    

    int    count = 0 ;

    for (Iterator i=begin; i!=end; ++i)

    {

        sum += f(*i);

        ++count;

    }

}

However, I now want to use the "Triangulation_2::finite_vertices_iterator"

as the iterator, and I want to apply a functor that requires access to the

vertex_handle. - This is a problem because the algorithm above dereferences

the iterator and gives me a plain vertex: The problem is that dereferencing

the iterator that CGAL gives us causes us to lose information.

I'm looking for a solution that keeps the same input parameters (an iterator 

with '::value_type' that corresponds to the argument of the functor). 

But may work differently 'under the hood' - i.e. we have a special 

helper function "apply(f, x)" that applies a function to an 

iterator. I tried to use some dirty 'template magick' tricks to do this but 

the ideas I had require features that are only reliably available in C++11.

Any ideas?