13     for(PropertyVector::iterator it = properties.begin(); it != properties.end(); ++it)
 
   15         flux << std::setw(
detail::keyWidth) << it->first << 
": " << it->second << std::endl;
 
std::vector< std::pair< std::string, std::string > > PropertyVector
PropertyVector is a vector of pair, because the order of properties matters to us. 
 
const std::string separator
 
std::ostream & operator<<(std::ostream &flux, const InputFile &input)
 
PropertyVector asVector() const 
Same data with a specific order.