RetroSearch Browse

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://en.cppreference.com/w/cpp/language/../algorithm/../numeric/math/fpclassify.html below:

std::fpclassify - cppreference.com

(1) int fpclassify( float num ); int fpclassify( double num ); int fpclassify( long double num ); (since C++11)
(until C++23)

constexpr int fpclassify( /* floating-point-type */ num );

(since C++23)

template< class Integer > int fpclassify( Integer num );

(A) (since C++11)
(constexpr since C++23)

1) Categorizes floating point value num into the following categories: zero, subnormal, normal, infinite, NAN, or implementation-defined category. The library provides overloads of std::fpclassify 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.

[edit] Parameters num - floating-point or integer value [edit] Return value

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

[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::fpclassify(num) has the same effect as std::fpclassify(static_cast<double>(num)).

[edit] Example

#include <cfloat>
#include <cmath>
#include <iostream>
 
auto 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

[edit] See also checks if the given number has finite value
(function) [edit] checks if the given number is infinite
(function) [edit] checks if the given number is NaN
(function) [edit] checks if the given number is normal
(function) [edit] provides an interface to query properties of all fundamental numeric types
(class template) [edit]

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4