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# std::is_base_of

From cppreference.com
< cpp‎ | types

Defined in header `<type_traits>` |  |
template< class Base, class Derived > struct is_base_of; |  | (since C++11)

If `Derived` is derived from `Base` or if both are the same non-union class, provides the member constant `value` equal to true. Otherwise `value` is false.

Requires that `Derived` is a complete type if it is not the same type as `Base` and if both `Base` and `Derived` are class types.

## Inherited from std::integral_constant

### Member constants

value [static] | true if `Derived` is derived from `Base` , false otherwise (public static member constant)

### Member functions

operator bool | converts the object to bool, returns `value` (public member function)

### Member types

Type | Definition
`value_type` | `bool`
`type` | std::integral_constant<bool, value>

### [edit] Example

Run this code

    #include <iostream>
    #include <type_traits>

    class A {};

    class B : A {};

    class C {};

    int main()
    {
        std::cout << std::boolalpha;
        std::cout << "a2b: " << std::is_base_of<A, B>::value << '\n';
        std::cout << "b2a: " << std::is_base_of<B, A>::value << '\n';
        std::cout << "c2b: " << std::is_base_of<C, B>::value << '\n';
    }

Output:

    a2b: true
    b2a: false
    c2b: false

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