NAME¶

std::is_floating_point - std::is_floating_point

Synopsis¶

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

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

Inherited from std::integral_constant

Member constants¶

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

Member functions¶

operator bool converts the object to bool, returns value
(public member function)
operator() returns value
(C++14) (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 identifies the IEC 559/IEEE 754 floating-point types
[static] (public static member constant of std::numeric_limits<T>)
is_integral checks if a type is an integral type
(C++11) (class template)
is_arithmetic checks if a type is an arithmetic type
(C++11) (class template)
floating_point specifies that a type is a floating-point type
(C++20) (concept)