Namespaces
Variants
Views
Actions

Difference between revisions of "cpp/numeric/math/fpclassify"

From cppreference.com
< cpp‎ | numeric‎ | math
(+integral type overloads)
m (Text replace - "Integral arg" to "IntegralType arg")
Line 13: Line 13:
 
}}
 
}}
 
{{dcl | since=c++11 | num=4 |
 
{{dcl | since=c++11 | num=4 |
−
int fpclassify( Integral arg );
+
int fpclassify( IntegralType arg );
 
}}
 
}}
 
{{dcl end}}
 
{{dcl end}}

Revision as of 20:04, 17 October 2018

 
C++
 
Numerics library
Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Floating-point environment (C++11)
Complex numbers
Numeric array (valarray)
Pseudo-random number generation
Factor operations
(C++17)
(C++17)
Interpolations
(C++20)
(C++20)
Saturation arithmetic
(C++26)
(C++26)
(C++26)
(C++26)
(C++26)

Generic numeric operations
Bit operations
(C++20)    
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++23)
(C++20)
 
Common mathematical functions
Functions
Basic operations
(C++11)  
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)(C++11)(C++11)
Exponential functions
(C++11)
(C++11)

(C++11)
(C++11)
Power functions
(C++11)
(C++11)
Trigonometric and
hyperbolic functions
(C++11)
(C++11)
(C++11)

Error and gamma functions
(C++11)
(C++11)
(C++11)
(C++11)
Nearest integer floating point operations
(C++11)(C++11)(C++11)
(C++11)
(C++11)
(C++11)(C++11)(C++11)
Floating point manipulation functions
(C++11)(C++11)
(C++11)
(C++11)
(C++11)(C++11)
(C++11)
Classification and comparison
fpclassify
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
Types
(C++11)
(C++11)
(C++11)
Macro constants
 
Defined in header <cmath>
int fpclassify( float arg );
 (1) (since C++11)
int fpclassify( double arg );
 (2) (since C++11)
int fpclassify( long double arg );
 (3) (since C++11)
int fpclassify( IntegralType arg );
 (4) (since C++11)
1-3) Categorizes floating point value arg into the following categories: zero, subnormal, normal, infinite, NAN, or implementation-defined category.
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).

Contents

Parameters

arg - floating point value

Return value

one of FP_INFINITE, FP_NAN, FP_NORMAL, FP_SUBNORMAL, FP_ZERO or implementation-defined type, specifying the category of arg.

Example

Run this code
#include <iostream>
#include <cmath>
#include <cfloat>
 
const char* show_classification(double x) {
    switch(std::fpclassify(x)) {
        case FP_INFINITE:  return "Inf";
        case FP_NAN:       return "NaN";
        case FP_NORMAL:    return "normal";
        case FP_SUBNORMAL: return "subnormal";
        case FP_ZERO:      return "zero";
        default:           return "unknown";
    }
}
int main()
{
    std::cout << "1.0/0.0 is " << show_classification(1/0.0) << '\n'
              << "0.0/0.0 is " << show_classification(0.0/0.0) << '\n'
              << "DBL_MIN/2 is " << show_classification(DBL_MIN/2) << '\n'
              << "-0.0 is " << show_classification(-0.0) << '\n'
              << "1.0 is " << show_classification(1.0) << '\n';
}

Output: 

1.0/0.0 is Inf
0.0/0.0 is NaN
DBL_MIN/2 is subnormal
-0.0 is zero
1.0 is normal

See also

(C++11)
 checks if the given number has finite 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]
provides an interface to query properties of all fundamental numeric types
(class template) [edit]
C documentation for fpclassify
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/numeric/math/fpclassify&oldid=106585"