(Re)named std::pair members

Question

Instead of writing town->first I would like to write town->name. Inline named accessors (Renaming first and second of a map iterator and Name

Answer 1

Although not perfect, it is possible to use tagged data:

template 
typename tag_type::type& get(pair_type& p);

typedef std::pair city;
struct name { typedef std::string type; };
struct zipcode { typedef int type; };

template <>
std::string& get(city& city)
{
   return city.first;
}

template <>
int& get(city& city)
{
   return city.second;
}

int main()
{
   city c("new york", 10001);
   std::string n = get(c);
   int z = get(c);
}

But as Ben Voigt says: struct city { string name; int zipcode; }; would pretty much always be better.

EDIT: Templates probably are an overkill, you could use free functions in a namespace instead. This still does not solve type safety issues, as any std::pair are the same type as any other std::pair:

namespace city
{
   typedef std::pair type;

   std::string& name(type& city)
   {
      return city.first;
   }

   int& zipcode(type& city)
   {
      return city.second;
   }
}

int main()
{
   city::type c("new york", 10001);
   std::string n = city::name(c);
   int z = city::zipcode(c);
}