#include <iostream>
#include <cmath>

#include <boost/mpl/vector.hpp>
#include <boost/mpl/push_back.hpp>
#include <boost/mpl/times.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/mpl/fold.hpp>

namespace mpl = boost::mpl;

namespace client {

    // pow(Value, Exponent)
    template <typename Base, typename Exponent>
    struct pow
    : mpl::times<
        Base,
        pow<Base, mpl::int_<Exponent::value - 1 > >
    > ::type {
    };

    // specialization for 0
    template <typename Value>
    struct pow<Value, mpl::int_ < 0 > >
    : mpl::int_ < 1 > ::type {
    };

    // the pow10 mpl function
    template <typename Exponent>
    struct pow10
    : pow<mpl::int_ < 10 >, Exponent > {
    };
}

template <typename U>
void display_pow(U x) {
    std::cout << "[mpl] pow10("
            << U::value
            << ")="
            << client::pow10< U > ()
            << " (real value="
            << std::pow(10.0, float(U::value))
            << ")"
            << std::endl;
}

int main() {
    
    display_pow(mpl::int_ < 0 > ());
    display_pow(mpl::int_ < 1 > ());
    display_pow(mpl::int_ < 3 > ());

#if 0 // concept
    pow10_vector<0,7> pow10;
    assert(pow10(2) == 100);
#endif
    
    return 0;
}