#include <iostream>
 #include <type_traits>

 using namespace std;

 int main(){

   cout << boolalpha << endl;

   cout << "is_const<add_const<int>::type>::value: " <<  is_const<add_const<int>::type>::value << endl;
   cout << "is_const<remove_const<const int>::type>::value: " << is_const<remove_const<const int>::type>::value << endl;

   cout << endl;

   typedef add_const<int>::type myConstInt;
   cout << "is_const<myConstInt>::value: " << is_const<myConstInt>::value << endl;
   typedef const int myConstInt2;
   cout << "is_same<myConstInt,myConstInt2>::value: " << is_same<myConstInt,myConstInt2>::value << endl;

   cout << endl;

   int fir= 1;
   int& refFir1= fir;
   using refToIntType= typename add_lvalue_reference<int>::type;
   refToIntType refFir2= fir;

   cout << "(fir,refFi1r,refFir2): "  << "(" << fir << "," << refFir1 << "," << refFir2 << ")" << endl;

   fir= 2;

   cout << "(fir,refFir,refFir2): "  << "(" << fir << "," << refFir1 << "," << refFir2 << ")" << endl;

   cout << endl;

 }