#include <string>
#include <iostream>
#include <map>
#include <utility>
#include <array>
 
using namespace std;
 
int main()
{
        map< array<double, 3>, string> mapa;

        array<double, 3> a = {1,2,3};
        array<double, 3> b = {1,0,0};

        mapa[a] = "a";
        mapa[b] = "b";
 
   cout << mapa[a] << endl; //This print ok.

   for(auto ii=mapa.begin(); ii!=mapa.end(); ++ii)
   {
       cout << '{' << ii->first[0] << ','
                   << ii->first[1] << ','
                   << ii->first[2] << "} : " << ii->second << '\n';
   }
}