Standard library header <ratio> (C++11)

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C++
Standard library headers

This header is part of the compile-time rational arithmetic library.

Classes

(C++11)
represents exact rational fraction
(class template)
Arithmetic
(C++11)
adds two ratio objects at compile-time
(alias template)
(C++11)
subtracts two ratio objects at compile-time
(alias template)
(C++11)
multiplies two ratio objects at compile-time
(alias template)
(C++11)
divides two ratio objects at compile-time
(alias template)
Comparison
(C++11)
compares two ratio objects for equality at compile-time
(class template)
(C++11)
compares two ratio objects for inequality at compile-time
(class template)
(C++11)
compares two ratio objects for less than at compile-time
(class template)
(C++11)
compares two ratio objects for less than or equal to at compile-time
(class template)
(C++11)
compares two ratio objects for greater than at compile-time
(class template)
(C++11)
compares two ratio objects for greater than or equal to at compile-time
(class template)
Type Aliases
quecto (C++26) std:: ratio < 1 , 1000000000000000000000000000000 > , if std::intmax_t can represent the denominator
ronto (C++26) std:: ratio < 1 , 1000000000000000000000000000 > , if std::intmax_t can represent the denominator
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
ronna (C++26) std:: ratio < 1000000000000000000000000000 , 1 > , if std::intmax_t can represent the numerator
quetta (C++26) std:: ratio < 1000000000000000000000000000000 , 1 > , if std::intmax_t can represent the numerator

Synopsis 

namespace std {
 
    // class template ratio
    template <intmax_t N, intmax_t D = 1>
    class ratio {
    public:
        typedef ratio<num, den> type;
        static constexpr intmax_t num;
        static constexpr intmax_t den;
    };
 
 
    // ratio arithmetic            
    template <class R1, class   R2> using   ratio_add      = /*ratio*/;
    template <class R1, class   R2> using   ratio_subtract = /*ratio*/;
    template <class R1, class   R2> using   ratio_multiply = /*ratio*/;
    template <class R1, class   R2> using   ratio_divide   = /*ratio*/;
 
    // ratio comparison            
    template <class R1, class R2> struct ratio_equal;           
    template <class R1, class R2> struct ratio_not_equal;           
    template <class R1, class R2> struct ratio_less;      
    template <class R1, class R2> struct ratio_less_equal;          
    template <class R1, class R2> struct ratio_greater;         
    template <class R1, class R2> struct ratio_greater_equal;  
 
    // convenience SI typedefs
    typedef ratio<1, 1000000000000000000000000000000> quecto;
    typedef ratio<1,    1000000000000000000000000000> ronto;         
    typedef ratio<1,       1000000000000000000000000> yocto;
    typedef ratio<1,          1000000000000000000000> zepto;
    typedef ratio<1,             1000000000000000000> atto;   
    typedef ratio<1,                1000000000000000> femto;  
    typedef ratio<1,                   1000000000000> pico;   
    typedef ratio<1,                      1000000000> nano;   
    typedef ratio<1,                         1000000> micro;  
    typedef ratio<1,                            1000> milli;  
    typedef ratio<1,                             100> centi;  
    typedef ratio<1,                              10> deci;   
    typedef ratio<                             10, 1> deca;   
    typedef ratio<                            100, 1> hecto;  
    typedef ratio<                           1000, 1> kilo;   
    typedef ratio<                        1000000, 1> mega;   
    typedef ratio<                     1000000000, 1> giga;   
    typedef ratio<                  1000000000000, 1> tera;   
    typedef ratio<               1000000000000000, 1> peta;   
    typedef ratio<            1000000000000000000, 1> exa;    
    typedef ratio<         1000000000000000000000, 1> zetta;
    typedef ratio<      1000000000000000000000000, 1> yotta;
    typedef ratio<   1000000000000000000000000000, 1> ronna;
    typedef ratio<1000000000000000000000000000000, 1> quetta;
 
}
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