std::make_unsigned

// make_unsigned
#include <iostream>
#include <type_traits>
enum ENUM1 {a,b,c};
enum class ENUM2 : char {a,b,c};
int main() {
  typedef std::make_unsigned<int>::type A;                // unsigned int
  typedef std::make_unsigned<unsigned>::type B;           // unsigned int
  typedef std::make_unsigned<const unsigned>::type C;     // const unsigned int
  typedef std::make_unsigned<ENUM1>::type D;              // unsigned int
  typedef std::make_unsigned<ENUM2>::type E;              // unsigned char
  std::cout << std::boolalpha;
  std::cout << "typedefs of unsigned int:" << std::endl;
  std::cout << "A: " << std::is_same<unsigned,A>::value << std::endl;
  std::cout << "B: " << std::is_same<unsigned,B>::value << std::endl;
  std::cout << "C: " << std::is_same<unsigned,C>::value << std::endl;
  std::cout << "D: " << std::is_same<unsigned,D>::value << std::endl;
  std::cout << "E: " << std::is_same<unsigned,E>::value << std::endl;
  return 0;
}