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<ratio>

Include the standard header <ratio> to define constants and templates that are used to store and manipulate rational numbers at compile time.

#include <ratio>

ratio Structure

template <intmax_t N, intmax_t D = 1>
struct ratio
{
    static constexpr intmax_t num;
    static constexpr intmax_t den;
    typedef ratio<num, den> type;
};

The ratio Structure defines the static constants num and den such that num / den == N / D and num and den have no common factors. num / den is the value that is represented by the template class. Therefore, type designates the instantiation ratio<N0, D0> for which num == N0 and den == D0.

Specializations

<ratio> also defines specializations of ratio that have the following form.

template <class R1, class R2> struct ratio_specialization

Each specialization takes two template parameters that must also be specializations of ratio. The value of type is determined by an associated logical operation.

Name

type Value

ratio_add

R1 + R2

ratio_divide

R1 / R2

ratio_equal

R1 == R2

ratio_greater

R1 > R2

ratio_greater_equal

R1 >= R2

ratio_less

R1 < R2

ratio_less_equal

R1 <= R2

ratio_multiply

R1 * R2

ratio_not_equal

!(R1 == R2)

ratio_subtract

R1 - R2

typedefs

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;

See Also

Other Resources

C++ Standard Library Header Files