Use of for_each on map elements

Question

I have a map where I\'d like to perform a call on every data type object member function. I yet know how to do this on any sequence but, is it possible to do it on an associativ

Answer 1

I wrote this awhile back to do just what you're looking for.

namespace STLHelpers
{
    //
    // iterator helper type for iterating through the *values* of key/value collections
    //

    /////////////////////////////////////////////
    template
    struct _value_iterator
    {
        explicit _value_iterator(typename _traits::iterator_type _it)
            : it(_it)
        {
        }

        _value_iterator(const _value_iterator &_other)
            : it(_other.it)
        {
        }

        friend bool operator==(const _value_iterator &lhs, const _value_iterator &rhs)
        {
            return lhs.it == rhs.it;
        }

        friend bool operator!=(const _value_iterator &lhs, const _value_iterator &rhs)
        {
            return !(lhs == rhs);
        }

        _value_iterator &operator++()
        {
            ++it;
            return *this;
        }

        _value_iterator operator++(int)
        {
            _value_iterator t(*this);
            ++*this;
            return t;
        }

        typename _traits::value_type &operator->()
        {
            return **this;
        }

        typename _traits::value_type &operator*()
        {
            return it->second;
        }

        typename _traits::iterator_type it;
    };

    template
    struct _map_iterator_traits
    {
        typedef typename _tyMap::iterator iterator_type;
        typedef typename _tyMap::mapped_type value_type;
    };

    template
    struct _const_map_iterator_traits
    {
        typedef typename _tyMap::const_iterator iterator_type;
        typedef const typename _tyMap::mapped_type value_type;
    };
}