Is it possible to print a variable's type in standard C++?

Question

For example:

int a = 12;
cout << typeof(a) << endl;

Expected output:

int

Answer 1

In C++11, we have decltype. There is no way in standard c++ to display exact type of variable declared using decltype. We can use boost typeindex i.e type_id_with_cvr (cvr stands for const, volatile, reference) to print type like below.

#include 
#include 

using namespace std;
using boost::typeindex::type_id_with_cvr;

int main() {
  int i = 0;
  const int ci = 0;
  cout << "decltype(i) is " << type_id_with_cvr().pretty_name() << '\n';
  cout << "decltype((i)) is " << type_id_with_cvr().pretty_name() << '\n';
  cout << "decltype(ci) is " << type_id_with_cvr().pretty_name() << '\n';
  cout << "decltype((ci)) is " << type_id_with_cvr().pretty_name() << '\n';
  cout << "decltype(std::move(i)) is " << type_id_with_cvr().pretty_name() << '\n';
  cout << "decltype(std::static_cast(i)) is " << type_id_with_cvr(i))>().pretty_name() << '\n';
  return 0;
}