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std::isfinite

From cppreference.com
< cpp‎ | numeric‎ | math
 
 
 
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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)
Defined in header <cmath>
template< class Integer >
bool isfinite( Integer num );
(A) (since C++11)
(constexpr since C++23)
1) 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.(since C++23)
A) Additional overloads are provided for all integer types, which are treated as double.

Contents

[edit] Parameters

num - floating-point or integer value

[edit] Return value

true if num has finite value, false otherwise.

[edit] Notes

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)).

[edit] 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';
}

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

[edit] See also

categorizes the given floating-point value
(function) [edit]
(C++11)
checks if the given number is infinite
(function) [edit]
(C++11)
checks if the given number is NaN
(function) [edit]
(C++11)
checks if the given number is normal
(function) [edit]
C documentation for isfinite