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# std::isfinite

From cppreference.com
< 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( Integral 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 `from` argument of any integral type. Equivalent to (2) (the argument is cast to double).

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

true value if `arg` has finite value, false if `arg` is infinite or NaN

### [edit] Examples

Run this code

    #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

### [edit] See also

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

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