Standard library header <numbers> (C++20)

 

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Standard Library headers

Note: a slash '/' in a revision mark means that the header was deprecated and/or removed.

Language Support
<cstddef> <cstdlib> <version> (C++20) <limits> <climits>	<cfloat> <cstdint> (C++11) <new> <typeinfo>	<source_location> (C++20) <exception> <initializer_list> (C++11)   <compare> (C++20)	<coroutine> (C++20) <csignal> <csetjmp> <cstdarg>
Concepts
<concepts> (C++20)
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error> (C++11)
General utilities
<utility> <memory> <memory_resource> (C++17) <scoped_allocator> (C++11)   <expected> (C++23)	<bitset> <tuple> (C++11) <optional> (C++17) <any> (C++17)	<variant> (C++17) <type_traits> (C++11) <ratio> (C++11) <chrono> (C++11)	<typeindex> (C++11) <functional> <stacktrace> (C++23) <ctime>
Strings
<string> <string_view> (C++17) <cstring>	<charconv> (C++17) <format> (C++20)	<cctype> <cwctype>	<cwchar> <cuchar> (C++11)
Localization
<locale> <clocale>	<codecvt> (C++11/17)
Containers
<span> (C++20) <array> (C++11) <vector>	<deque> <forward_list> (C++11) <list>	<map> <set> <queue>	<unordered_map> (C++11) <unordered_set> (C++11) <stack>
Iterators
<iterator>
Ranges
<ranges> (C++20)
Algorithms
<algorithm>	<execution> (C++17)
Numerics
<complex> <random> (C++11)	<valarray> <numeric>	<bit> (C++20) <numbers> (C++20)	<cfenv> (C++11) <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<syncstream> (C++20) <spanstream> (C++23) <sstream> <fstream>	<cstdio> <cinttypes> (C++11) <strstream> (C++98/)
Regular expressions
<regex> (C++11)
Filesystem support
<filesystem> (C++17)
Thread support
<thread> (C++11) <atomic> (C++11) <mutex> (C++11)	<shared_mutex> (C++14) <condition_variable> (C++11)   <future> (C++11)	<stop_token> (C++20) <semaphore> (C++20)	<latch> (C++20) <barrier> (C++20)
C compatibility
<cstdbool> (C++11/17/20) <ccomplex> (C++11/17/20)	<ctgmath> (C++11/17/20) <cstdalign> (C++11/17/20)	<ciso646> (until C++20) <stdatomic.h>

 

This header is part of the numeric library.

Mathematical constants (since C++20)

The header <numbers> provides several mathematical constants, such as std::numbers::pi or std::numbers::sqrt2

Synopsis

namespace std::numbers {
  template<class T> inline constexpr T e_v          = /* unspecified */;
  template<class T> inline constexpr T log2e_v      = /* unspecified */;
  template<class T> inline constexpr T log10e_v     = /* unspecified */;
  template<class T> inline constexpr T pi_v         = /* unspecified */;
  template<class T> inline constexpr T inv_pi_v     = /* unspecified */;
  template<class T> inline constexpr T inv_sqrtpi_v = /* unspecified */;
  template<class T> inline constexpr T ln2_v        = /* unspecified */;
  template<class T> inline constexpr T ln10_v       = /* unspecified */;
  template<class T> inline constexpr T sqrt2_v      = /* unspecified */;
  template<class T> inline constexpr T sqrt3_v      = /* unspecified */;
  template<class T> inline constexpr T inv_sqrt3_v  = /* unspecified */;
  template<class T> inline constexpr T egamma_v     = /* unspecified */;
  template<class T> inline constexpr T phi_v        = /* unspecified */;
 
  template<floating_point T> inline constexpr T e_v<T>          = /* see description */;
  template<floating_point T> inline constexpr T log2e_v<T>      = /* see description */;
  template<floating_point T> inline constexpr T log10e_v<T>     = /* see description */;
  template<floating_point T> inline constexpr T pi_v<T>         = /* see description */;
  template<floating_point T> inline constexpr T inv_pi_v<T>     = /* see description */;
  template<floating_point T> inline constexpr T inv_sqrtpi_v<T> = /* see description */;
  template<floating_point T> inline constexpr T ln2_v<T>        = /* see description */;
  template<floating_point T> inline constexpr T ln10_v<T>       = /* see description */;
  template<floating_point T> inline constexpr T sqrt2_v<T>      = /* see description */;
  template<floating_point T> inline constexpr T sqrt3_v<T>      = /* see description */;
  template<floating_point T> inline constexpr T inv_sqrt3_v<T>  = /* see description */;
  template<floating_point T> inline constexpr T egamma_v<T>     = /* see description */;
  template<floating_point T> inline constexpr T phi_v<T>        = /* see description */;
 
  inline constexpr double e          = e_v<double>;
  inline constexpr double log2e      = log2e_v<double>;
  inline constexpr double log10e     = log10e_v<double>;
  inline constexpr double pi         = pi_v<double>;
  inline constexpr double inv_pi     = inv_pi_v<double>;
  inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
  inline constexpr double ln2        = ln2_v<double>;
  inline constexpr double ln10       = ln10_v<double>;
  inline constexpr double sqrt2      = sqrt2_v<double>;
  inline constexpr double sqrt3      = sqrt3_v<double>;
  inline constexpr double inv_sqrt3  = inv_sqrt3_v<double>;
  inline constexpr double egamma     = egamma_v<double>;
  inline constexpr double phi        = phi_v<double>;
}