std::isfinite

< cpp‎ | numeric‎ | math
Defined in header <cmath>
bool isfinite( float arg );
 (1) (since C++11)
bool isfinite( double arg );
 (2) (since C++11)
bool isfinite( long double arg );
 (3) (since C++11)
bool isfinite( IntegralType arg );
 (4) (since C++11)
1-3) Determines if the given floating point number arg has finite value i.e. it is normal, subnormal or zero, but not infinite or NaN.
4) A set of overloads or a function template accepting the arg argument of any integral type. Equivalent to (2) (the argument is cast to double).

Parameters

arg - floating point value

Return value

true if arg has finite value, false otherwise

Examples

#include <iostream>
#include <cmath>
#include <cfloat>
 
int main()
{
    std::cout << std::boolalpha
              << "isfinite(NaN) = " << std::isfinite(NAN) << '\n'
              << "isfinite(Inf) = " << std::isfinite(INFINITY) << '\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(0.0) = true
isfinite(exp(800)) = false
isfinite(DBL_MIN/2.0) = true

See also

(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)