Isnormal

Defined in header <cmath>.

Description

Determines if the given floating point number num is normal, i.e. is neither zero, subnormal, infinite, nor NaN.
​The library provides overloads for all cv-unqualified floating-point types as the type of the parameter num (since C++23).

​Additional Overloads are provided for all integer types, which are treated as double.

Declarations

C++23

// 1)
constexpr bool isnormal( /* floating-point-type */ num );

Additional Overloads

// 2)
template< class Integer >
constexpr bool isnormal( Integer num );

C++11

// 1)
bool isnormal( float num );
// 2)
bool isnormal( double num );
// 3)
bool isnormal( long double num );

Additional Overloads

// 4)
template< class Integer >
bool isnormal( Integer num );

Parameters

​num - floating-point or integer value

Return value

true if num is normal, false otherwise.

Notes

The additional overloads are not required to be provided exactly as Additional Overloads. They only need to be sufficient to ensure that for their argument num of integer type,
std::isnormal(num) has the same effect as std::isnormal(static_cast<double>(num)).

Examples

#include <cfloat>
#include <cmath>
#include <iostream>
 
int main()
{
    std::cout 
        << std::boolalpha
        << "isnormal(NaN) = " 
        << std::isnormal(NAN) << '\n'
        << "isnormal(Inf) = " 
        << std::isnormal(INFINITY) << '\n'
        << "isnormal(0.0) = " 
        << std::isnormal(0.0) << '\n'
        << "isnormal(DBL_MIN/2.0) = " 
        << std::isnormal(DBL_MIN / 2.0) << '\n'
        << "isnormal(1.0) = " 
        << std::isnormal(1.0) << '\n';
}

Result

isnormal(NaN) = false
isnormal(Inf) = false
isnormal(0.0) = false
isnormal(DBL_MIN/2.0) = false
isnormal(1.0) = true