A practical walkthrough of using the Curiously Recurring Template Pattern (CRTP) in C++ to eliminate duplicate comparison operator definitions. Starting from a naive class with six manually written operators, the post builds a reusable `comparison_impl` base class that derives `!=`, `<=`, and `>=` from just three user-provided operators (`==`, `<`, `>`). It also covers the Barton-Nackman trick for symmetric comparisons and uses SFINAE with `std::enable_if` and `std::is_same` to resolve ambiguous overload errors when comparing objects of the same type.
Table of contents
The ExampleComparison, The Other Way AroundThe Fat Friend Who Likes EatingComparison, The Other Way Around, ReloadedSFINAE to the RescueWhat We GotSort: