std::is_floating_point

 

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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.

Template parameters

T

-

a type to check

Helper variable template

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

Inherited from std::integral_constant

Member constants

value [static]

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)
operator() (C++14)	returns value (public member function)

Member types

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

Possible implementation

template< class T > struct is_floating_point : std::integral_constant< bool, // 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 > {};

Example

Run this code

#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';
}

Output:

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

See also

is_iec559 [static]	identifies the IEC 559/IEEE 754 floating-point types (public static member constant of std::numeric_limits<T>)
is_integral (C++11)	checks if a type is an integral type (class template)
is_arithmetic (C++11)	checks if a type is an arithmetic type (class template)
floating_point (C++20)	specifies that a type is a floating-point type (concept)