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std::ratio(3) C++ Standard Libary std::ratio(3) NAME std::ratio - std::ratio Synopsis Defined in header <ratio> template< std::intmax_t Num, (since C++11) std::intmax_t Denom = 1 > class ratio; The class template std::ratio provides compile-time rational arith- metic support. Each instantiation of this template exactly represents any finite rational number as long as its numerator Num and denominator Denom are representable as compile-time constants of type std::intmax_t. In addition, Denom may not be zero and may not be equal to the most negative value. The static data members num and den representing the numerator and denominator are calculated by dividing Num and Denom by their greatest common divi- sor. However, two std::ratio with different Num or Denom are distinct types even if they represent the same rational number (after reduction). A ratio type can be reduced to the lowest terms via its type member: std::ratio<3, 6>::type is std::ratio<1, 2>. Several convenience typedefs that correspond to the SI ratios are provided by the standard library: Defined in header <ratio> Type Definition yocto std::ratio<1, 1000000000000000000000000>, if std::intmax_t can represent the denominator zepto std::ratio<1, 1000000000000000000000>, if std::intmax_t can represent the denominator atto std::ratio<1, 1000000000000000000> femto std::ratio<1, 1000000000000000> pico std::ratio<1, 1000000000000> nano std::ratio<1, 1000000000> micro std::ratio<1, 1000000> milli std::ratio<1, 1000> centi std::ratio<1, 100> deci std::ratio<1, 10> deca std::ratio<10, 1> hecto std::ratio<100, 1> kilo std::ratio<1000, 1> mega std::ratio<1000000, 1> giga std::ratio<1000000000, 1> tera std::ratio<1000000000000, 1> peta std::ratio<1000000000000000, 1> exa std::ratio<1000000000000000000, 1> zetta std::ratio<1000000000000000000000, 1>, if std::intmax_t can represent the numerator yotta std::ratio<1000000000000000000000000, 1>, if std::intmax_t can represent the numerator Member types Member type Definition type std::ratio<num, den> Member objects constexpr intmax_t num constexpr value of type std::intmax_t equal to sign(Denom) * [static] Num / gcd(Num, Denom) (public static member constant) constexpr intmax_t den constexpr value of type std::intmax_t equal to abs(Denom) / [static] gcd(Num, Denom) (public static member constant) See also Mathematical constants (C++20) provides several mathematical con- stants, such as std::numbers::e for e http://cppreference.com 2022.07.31 std::ratio(3)
NAME | Synopsis | Member types | Member objects | See also
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