#include #include class A {}; enum B : unsigned {}; enum class C : unsigned {}; int main() { std::cout << std::boolalpha; std::cout << std::is_unsigned::value << '\n'; std::cout << std::is_unsigned::value << '\n'; std::cout << std::is_unsigned::value << '\n'; std::cout << std::is_unsigned::value << '\n'; std::cout << std::is_unsigned::value << '\n'; std::cout << std::is_unsigned::value << '\n'; }