C++11 enum attribute set

#include <bitset>

namespace {

  namespace Source {
    // not an enum class because these have no implicit conversion to int
    enum Type {
      analog_radio,
      internet_radio,
      bluetooth
    };
    // keep updated when adding new Type
    constexpr std::size_t size()
    {
      return Source::bluetooth + 1;
    }
  }
  typedef std::bitset<Source::size()> SourceSet;
}

int main()
{
  SourceSet attributes;
  attributes[Source::analog_radio] = true;
  attributes[Source::bluetooth] = true;
  return 0;
}