< cpp‎ | types
Metaprogramming library
Type traits
Type categories
Type properties
(C++11)(until C++20*)
(C++11)(deprecated in C++20)
Type trait constants
Supported operations
Relationships and property queries
Type modifications
Type transformations
(C++11)(deprecated in C++23)
(C++11)(deprecated in C++23)

(C++11)(until C++20*)(C++17)
Compile-time rational arithmetic
Compile-time integer sequences
Defined in header <type_traits>
template< class T >
struct is_floating_point;
(since C++11)

std::is_floating_point is a UnaryTypeTrait.

Checks whether T is a floating-point type. Provides the member constant value which is equal to true, if T is the type float, double, long double, or any extended floating-point types (std::float16_t, std::float32_t, std::float64_t, std::float128_t, or std::bfloat16_t)(since C++23), including any cv-qualified variants. Otherwise, value is equal to false.

If the program adds specializations for std::is_floating_point or std::is_floating_point_v, the behavior is undefined.


[edit] Template parameters

T - a type to check

[edit] Helper variable template

template< class T >
inline constexpr bool is_floating_point_v = is_floating_point<T>::value;
(since C++17)

Inherited from std::integral_constant

Member constants

true if T is a floating-point type (possibly cv-qualified), false otherwise
(public static member constant)

Member functions

operator bool
converts the object to bool, returns value
(public member function)
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_floating_point
     : std::integral_constant<
         // Note: standard floating-point types
         std::is_same<float, typename std::remove_cv<T>::type>::value
         || std::is_same<double, typename std::remove_cv<T>::type>::value
         || std::is_same<long double, typename std::remove_cv<T>::type>::value
         // Note: extended floating-point types (C++23, if supported)
         || std::is_same<std::float16_t, typename std::remove_cv<T>::type>::value
         || std::is_same<std::float32_t, typename std::remove_cv<T>::type>::value
         || std::is_same<std::float64_t, typename std::remove_cv<T>::type>::value
         || std::is_same<std::float128_t, typename std::remove_cv<T>::type>::value
         || std::is_same<std::bfloat16_t, typename std::remove_cv<T>::type>::value
     > {};

[edit] Example

#include <iostream>
#include <type_traits>
class A {};
int main() 
    std::cout << std::boolalpha;
    std::cout << "      A: " << std::is_floating_point<A>::value << '\n';
    std::cout << "  float: " << std::is_floating_point<float>::value << '\n';
    std::cout << " float&: " << std::is_floating_point<float&>::value << '\n';
    std::cout << " double: " << std::is_floating_point<double>::value << '\n';
    std::cout << "double&: " << std::is_floating_point<double&>::value << '\n';
    std::cout << "    int: " << std::is_floating_point<int>::value << '\n';


      A: false
  float: true
 float&: false
 double: true
double&: false
    int: false

[edit] See also

identifies the IEC 559/IEEE 754 floating-point types
(public static member constant of std::numeric_limits<T>) [edit]
checks if a type is an integral type
(class template) [edit]
checks if a type is an arithmetic type
(class template) [edit]
specifies that a type is a floating-point type
(concept) [edit]