//********************************************************
// The following code example is taken from the book
//  C++20 - The Complete Guide
//  by Nicolai M. Josuttis (www.josuttis.com)
//  http://www.cppstd20.com
//
// The code is licensed under a
//  Creative Commons Attribution 4.0 International License
//  http://creativecommons.org/licenses/by/4.0/
//********************************************************


#include <compare>

class Value {
 private:
  long id;
  //...
 public:
  constexpr Value(long i) noexcept
   : id{i} {
  }
  //...
  // enable use of all equality and relational operators:
  auto operator<=> (const Value& rhs) const  = default;
};