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Showing content from https://cplusplus.com/reference/type_traits/is_base_of/ below:

class template

<type_traits>

std::is_base_of

template <class Base, class Derived> struct is_base_of;

Is base class of

Trait class that identifies whether Base is a base class of (or the same class as) Derived, without regard to their const and/or volatile qualification. Only classes that are not unions are considered.

The class inherits from integral_constant as being either true_type or false_type, depending on whether Derived inherits from Base.

Template parameters

Base: A type.
Derived: A type.

This shall be a complete type if both Base and Derived are different class types.

Member types Inherited from integral_constant:

Member constants Inherited from integral_constant:
member constant definition value either true or false
Member functions Inherited from integral_constant:

operator bool: Returns value (public member function)

Example

// is_base_of example
#include <iostream>
#include <type_traits>

struct A {};
struct B : A {};

int main() {
  std::cout << std::boolalpha;
  std::cout << "is_base_of:" << std::endl;
  std::cout << "int, int: " << std::is_base_of<int,int>::value << std::endl;
  std::cout << "A, A: " << std::is_base_of<A,A>::value << std::endl;
  std::cout << "A, B: " << std::is_base_of<A,B>::value << std::endl;
  std::cout << "A, const B: " << std::is_base_of<A,const B>::value << std::endl;
  std::cout << "A&, B&: " << std::is_base_of<A&,B&>::value << std::endl;
  std::cout << "B, A: " << std::is_base_of<B,A>::value << std::endl;
  return 0;
}

Output:

is_base_of:
int, int: false
A, A: true
A, B: true
A, const B: true
A&, B&: false
B, A: false