Class Address

06.16-customOrdering1/main.cpp:9–30

#include <string>

struct Address {
  std::string city;
  std::string street;
  uint32_t    street_no;

  auto operator<=>(const Address& rhs) const
  {
    // #A Sort city and street using their <=>
    if(const auto& cmp = city <=> rhs.city; cmp != 0) {
      return cmp;
    } else if(const auto& scmp = street <=> rhs.street;
              scmp != 0) {
      return scmp;
    }

    // #B Next, sort street_no ascending
    return rhs.street_no <=> street_no;
  }

  // #C The default should be good enough here
  bool operator==(const Address&) const = default;
};

int main()
{