How to check if a template parameter is an iterator type or not?

Question

template
struct is_iterator
{
    static const bool value = ??? // What to write ???
};

int main()
{
    assert(false == is_iterator::valu         


        

Answer 1

template < class T, class Enabler = void >
struct is_iterator : public boost::false_type { };

template < class T >
struct is_iterator< T, typename boost::enable_if_c<
        sizeof(*(*(T*)0)) + sizeof((*(T*)0)++) + sizeof(++(*(T*)0)) +
        sizeof((*(T*)0) == (*(T*)0)) + sizeof((*(T*)0) != (*(T*)0)) +
        sizeof((*(T*)0) = (*(T*)0)) >::type > : public boost::true_type { };