I want to apply some arbitrary function F on each element of a sequence through myfun class inherited from transform_view. I am unable to output the elements of the resultant sequence. Below is the whole code of my program #include <boost/mpl/int.hpp> #include <boost/mpl/apply.hpp> #include <boost/mpl/list_c.hpp> #include <boost/mpl/for_each.hpp> #include <boost/mpl/transform_view.hpp> #include <iostream> using namespace boost::mpl;     namespace mpl = boost::mpl; struct mysquare {     template< typename U > void operator()(U x)     {         static const int value = x*x;     } }; struct value_printer {     template< typename U > void operator()(U x)     {         std::cout << x << "   ";     } }; template<class F, class Seq> struct myfun:transform_view<Seq,F> {}; int main() {          using namespace std;     typedef list_c<int,0,1,2,3,4,5> numbers;     typedef myfun<mysquare,numbers>::type newnum;     for_each<numbers>(value_printer()); //    for_each<newnum>(value_printer());    // I don,t know what transform_view return }