Re: Template function overloading question

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Thu, 19 Jul 2007 08:10:10 -0400

Message-ID:

<f7nkb2$tgs$1@news.datemas.de>

Juha Nieminen wrote:

Victor Bazarov wrote:

I believe the common way to do that is to use not a member function
call, but a functor, and pass the container element to it:

    template<class C, class F>
    void ForEach(C c, F f) {
        for(typename Container::const_iterator iter = c.begin();
            iter != c.end(); ++iter)
        {
            f(*iter);
        }
    }

and when you need to use a member function, use binders (see
<functional> and 'bind1st', 'bind2nd', etc)

That didn't really answer my question.

OK, sorry about that. I thought you needed a generic commonly used
solution for doing 'ForEach' stuff, and you are just asking for the
syntax... My bad.

Here you go

    template<class C, class T>
    void ForEach(C c, void (T::*member)() const)
    {
        for(typename C::const_iterator iter = c.begin();
            iter != c.end(); ++iter)
        {
            ((*iter).*member)();
        }
    }

    template<class C>
    void ForEach(C c, void (*fptr)(typename C::value_type const&))
    {
        for(typename C::const_iterator iter = c.begin();
            iter != c.end(); ++iter)
        {
            fptr(*iter);
        }
    }

    #include <vector>
    struct A
    {
        void print() const {}
    };

    void print(A const&) {}

    int main()
    {
        std::vector<A> va;
        ForEach(va, &A::print);
        ForEach(va, print);
    }

Does *that* answer your question?

V
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