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# std::is_fundamental

From cppreference.com
< cpp‎ | types

Defined in header `<type_traits>` |  |
template< class T > struct is_fundamental; |  | (since C++11)

If `T` is a fundamental type (that is, arithmetic type, void, or nullptr_t), provides the member constant `value` equal true. For any other type, `value` is false.

### [edit] Template parameters

T | - | a type to check

### [edit] Helper variable template

template< class T > constexpr bool is_fundamental_v = is_fundamental<T>::value; |  | (since C++17)

[edit]

## Inherited from std::integral_constant

### Member constants

value [static] | true if `T` is a fundamental type , false otherwise (public static member constant)

### Member functions

operator bool | converts the object to bool, returns `value` (public member function)
operator() (C++14) | returns `value` (public member function)

### Member types

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

### [edit] Possible implementation

    template< class T >
    struct is_fundamental
      : std::integral_constant<
            bool,
            std::is_arithmetic<T>::value ||
            std::is_void<T>::value  ||
            std::is_same<std::nullptr_t, typename std::remove_cv<T>::type>::value
    > {};

### [edit] Example

Run this code

    #include <iostream>
    #include <type_traits>

    class A {};

    int main()
    {
        std::cout << std::boolalpha;
        std::cout << std::is_fundamental<A>::value << '\n';
        std::cout << std::is_fundamental<int>::value << '\n';
        std::cout << std::is_fundamental<int&>::value << '\n';
        std::cout << std::is_fundamental<int*>::value << '\n';
        std::cout << std::is_fundamental<float>::value << '\n';
        std::cout << std::is_fundamental<float&>::value << '\n';
        std::cout << std::is_fundamental<float*>::value << '\n';
    }

Output:

    false
    true
    false
    false
    true
    false
    false

### [edit] See also

is_compound (C++11) | checks if a type is compound type (class template) [edit]
is_arithmetic (C++11) | checks if a type is arithmetic type (class template) [edit]
is_void (C++11) | checks if a type is void (class template) [edit]
std::experimental::is_fundamental_v (library fundamentals TS) | variable template alias of `std::is_fundamental::value` (variable template) [edit]

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