#include <iostream>
#include <typeinfo>
#include <string_view>

template <class T>
constexpr std::string_view type_name()
{
    using namespace std;
#ifdef __clang__
    string_view p = __PRETTY_FUNCTION__;
    return string_view(p.data() + 34, p.size() - 34 - 1);
#elif defined(__GNUC__)
    string_view p = __PRETTY_FUNCTION__;
#  if __cplusplus < 201402
    return string_view(p.data() + 36, p.size() - 36 - 1);
#  else
    return string_view(p.data() + 49, p.find(';', 49) - 49);
#  endif
#elif defined(_MSC_VER)
    string_view p = __FUNCSIG__;
    return string_view(p.data() + 84, p.size() - 84 - 7);
#endif
}

using namespace std;

template<typename T>
void f(T& param)
{
    cout << "type_name<decltype(param)>() = " << type_name<decltype(param)>() << endl;
    cout << "type_name<T>() = " << type_name<T>() << endl;
    cout << endl;
}

int main()
{
    int x = 5;
    const int y = x;
    const int& z = x;
    f(x);
    f(y);
    f(z);
}