Defined in header <cmath> | ||
|---|---|---|
| (1) | ||
bool isfinite( float num ); bool isfinite( double num ); bool isfinite( long double num ); | (since C++11) (until C++23) | |
constexpr bool isfinite( /* floating-point-type */ num ); | (since C++23) | |
| Additional overloads | ||
Defined in header <cmath> | ||
template< class Integer > bool isfinite( Integer num ); | (A) | (since C++11) (constexpr since C++23) |
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. (since C++23)
double
| num | - | floating-point or integer value |
true if num has finite value, false otherwise.
The additional overloads are not required to be provided exactly as (A). 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)).
#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';
}Output:
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
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(C++11) | categorizes the given floating-point value (function) |
|
(C++11) | checks if the given number is infinite (function) |
|
(C++11) | checks if the given number is NaN (function) |
|
(C++11) | checks if the given number is normal (function) |
C documentation for isfinite |
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