Isfinite
Defined in header <cmath>
.
Description
Determines if the given floating point number num
has finite value i.e.
it is normal
, subnormal
or zero
, but not infinite
or NaN
.
The library provides overloads for all cv-unqualified floating-point types as the type of the parameter num
(od C++23).
Additional Overloads are provided for all integer types, which are treated as double.
Declarations
- C++23
- C++11
// 1)
constexpr bool isfinite( /* floating-point-type */ num );
// 2)
template< class Integer >
constexpr bool isfinite( Integer num );
// 1)
bool isfinite( float num );
// 2)
bool isfinite( double num );
// 3)
bool isfinite( long double num );
// 4)
template< class Integer >
bool isfinite( Integer num );
Parameters
num
- floating-point or integer value
Return value
true
if num
has finite value, 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::isfinite(num)
has the same effect as std::isfinite(static_cast<double>(num))
.
Examples
#include <cfloat>
#include <cmath>
#include <iostream>
int main()
{
std::cout
<< std::boolalpha
<< "isfinite(NaN) = "
<< std::isfinite(NAN) << '\n'
<< "isfinite(Inf) = "
<< std::isfinite(INFINITY) << '\n'
<< "isfinite(-Inf) = "
<< std::isfinite(-INFINITY) << '\n'
<< "isfinite(HUGE_VAL) = "
<< std::isfinite(HUGE_VAL) << '\n'
<< "isfinite(0.0) = "
<< std::isfinite(0.0) << '\n'
<< "isfinite(exp(800)) = "
<< std::isfinite(std::exp(800)) << '\n'
<< "isfinite(DBL_MIN/2.0) = "
<< std::isfinite(DBL_MIN / 2.0) << '\n';
}
isfinite(NaN) = false
isfinite(Inf) = false
isfinite(-Inf) = false
isfinite(HUGE_VAL) = false
isfinite(0.0) = true
isfinite(exp(800)) = false
isfinite(DBL_MIN/2.0) = true