Using the [overloaded] spaceship [<=>] operator.

#include <iostream>
#include <iomanip>
#include <string>
#include <compare>

using namespace std::literals::string_literals;

class Stump {
public:
  Stump(int val = 0) : val_ { val } {};
  Stump(Stump const & stmp) = default;
  Stump(Stump && stmp) = default;
  Stump & operator=(Stump const & stmp) = default;
  Stump & operator=(Stump && stmp) = default;

  auto operator <=>(Stump const & that) const {
    return val_ <=> that.val_;
  }

  auto operator==(Stump const & that) const {
    return val_ == that.val_;
  }

  int val(int val) {
    val_ = val;
    return val_;
  }

  int val(void) const {
    return val_;
  }

private:
  int val_;
};

int main() {
  std::cout << "C++ Version: "s << __cplusplus << std::endl;

  int av;
  int bv;
  std::cout << "Enter two integer values: "s;
  std::cout.flush();
  std::cin >> av >> bv;
  std::cout << std::endl;
  std::cout << "Input: "s << av << ' ' << bv << '\n';

  auto ay = Stump(av);
  auto be = Stump(bv);

  std::cout << ay.val() << " is"s
            << ((ay < be) ? " less than "s :
                (ay > be) ? " greater than "s :
                            " equal to "s)
            << be.val()
            << std::endl;

  std::cout << ay.val() << " is"s
            << ((ay <= be) ? " less than or equal to "s :
                (ay >= be) ? " greater than or equal to "s :
                             " not LE and not GE to "s)
            << be.val()
            << std::endl;

  std::cout << ay.val() << " is"s
            << ((ay != be) ? " not equal to "s :
                (ay == be) ? " equal to "s :
                             " not NE and not EQ to "s)
            << be.val()
            << std::endl;

  return 0;
}