filter.cpp

#include <iostream>

using namespace std;

template<typename T, T... values>
struct value_tuple {
    static const size_t size = sizeof...(values);
    typedef T value_type;
};

template<int i, typename ValueTuple>
struct value_get;

template<typename T, T front, T... values>
struct value_get<0, value_tuple<T, front, values...> > {
    typedef T value_type;
    static const T value = front;
};

template<int i, typename T, T front, T... values>
struct value_get<i, value_tuple<T, front, values...> > : public value_get<i - 1, value_tuple<T, values...> > {};

template <int index, typename input, typename filtered>
struct actual_filter;

template <int x, int... filtered>
struct actual_filter<x, value_tuple<int>, value_tuple<int, filtered...> > {
    typedef value_tuple<int, filtered...> Value;
};

template<int x, int front, int... input, int... filtered>
struct actual_filter<x, value_tuple<int, front, input...>, value_tuple<int, filtered...> > : public conditional<front < x, actual_filter<x, value_tuple<int, input...>, value_tuple<int, front, filtered...> >, actual_filter<x, value_tuple<int, input...>, value_tuple<int, filtered...> > >::type{};

template <int x, int... input>
struct filter_less {
    typedef typename actual_filter<x, value_tuple<int, input...>, value_tuple<int> >::Value Value;
};

template <size_t index, size_t end, typename values>
struct printer;

template <size_t index, size_t end, typename T, T... values>
struct printer<index, end, value_tuple<T, values...> > {
    static void doStuff() {
        cout << value_get<index, value_tuple<T, values>... >::value << endl;
        printer<index + 1, end, value_tuple<T, values...> >::doStuff();
    }
};

template <size_t index, typename T, T... values>
struct printer<index, index, value_tuple<T, values...> > {
    static void doStuff() {}
};


int main(int, char *[])
{
    typedef filter_less<30, 6, 5, 4, 67, 7, 3, 4, 5, 4>::Value Filtered;
    printer<0, Filtered::size, Filtered>::doStuff();
}