010_concepts_derived_from.cpp

#include <concepts>
 
class A {};
 
class B: public A {};
 
class C: private A{};
 
int main() {
    // std::derived_from == true only for public inheritance or exact same class
    static_assert( std::derived_from<B, B> == true );      // same class: true
    static_assert( std::derived_from<int, int> == false ); // same primitive type: false
    static_assert( std::derived_from<B, A> == true );      // public inheritance: true
    static_assert( std::derived_from<C, A> == false );     // private inheritance: false
 
    // std::is_base_of == true also for private inheritance
    static_assert( std::is_base_of_v<B, B> == true );      // same class: true
    static_assert( std::is_base_of_v<int, int> == false ); // same primitive type: false
    static_assert( std::is_base_of_v<A, B> == true );      // public inheritance: true
    static_assert( std::is_base_of_v<A, C> == true );      // private inheritance: true
}