operator+,-,*,/,%(std::chrono::duration)
template< class Rep1, class Period1, class Rep2, class Period2 > typename std::common_type<duration<Rep1,Period1>, duration<Rep2,Period2>>::type constexpr operator+( const duration<Rep1,Period1>& lhs, const duration<Rep2,Period2>& rhs ); |
(1) | |
template< class Rep1, class Period1, class Rep2, class Period2 > typename std::common_type<duration<Rep1,Period1>, duration<Rep2,Period2>>::type constexpr operator-( const duration<Rep1,Period1>& lhs, const duration<Rep2,Period2>& rhs ); |
(2) | |
template< class Rep1, class Period, class Rep2 > duration<typename std::common_type<Rep1,Rep2>::type, Period> constexpr operator*( const duration<Rep1,Period>& d, const Rep2& s ); |
(3) | |
template< class Rep1, class Rep2, class Period > duration<typename std::common_type<Rep1,Rep2>::type, Period> constexpr operator*( const Rep1& s, const duration<Rep2,Period>& d ); |
(4) | |
template< class Rep1, class Period, class Rep2 > duration<typename std::common_type<Rep1,Rep2>::type, Period> constexpr operator/( const duration<Rep1,Period>& d, const Rep2& s ); |
(5) | |
template< class Rep1, class Period1, class Rep2, class Period2 > typename std::common_type<Rep1,Rep2>::type constexpr operator/( const duration<Rep1,Period1>& lhs, const duration<Rep2,Period2>& rhs ); |
(6) | |
template< class Rep1, class Period, class Rep2 > duration<typename std::common_type<Rep1,Rep2>::type, Period> constexpr operator%( const duration<Rep1, Period>& d, const Rep2& s ); |
(7) | |
template< class Rep1, class Period1, class Rep2, class Period2 > typename std::common_type<duration<Rep1,Period1>, duration<Rep2,Period2>>::type constexpr operator%( const duration<Rep1,Period1>& lhs, const duration<Rep2,Period2>& rhs ); |
(8) |
Performs basic arithmetic operations between two durations or between a duration and a tick count.
1) Converts the two durations to their common type and creates a duration whose tick count is the sum of the tick counts after conversion.
2) Converts the two durations to their common type and creates a duration whose tick count is the
rhs
number of ticks subtracted from the
lhs
number of ticks after conversion.
3-4) Converts the duration
d
to one whose
rep
is the common type between
Rep1
and
Rep2
, and multiples the number of ticks after conversion by
s
. These overloads participate in overload resolution only if
s
is convertible to
typename std::common_type<Rep1, Rep2>::type
.
5) Converts the duration
d
to one whose
rep
is the common type between
Rep1
and
Rep2
, and divides the number of ticks after conversion by
s
. This overload participates in overload resolution only if
s
is convertible to
typename std::common_type<Rep1, Rep2>::type
and
Rep2
is not a specialization of
duration
.
6) Converts the two durations to their common type and divides the tick count of
lhs
after conversion by the tick count of
rhs
after conversion. Note that the return value of this operator is not a duration.
7) Converts the duration
d
to one whose
rep
is the common type between
Rep1
and
Rep2
, and creates a duration whose tick count is the remainder of the division of the tick count, after conversion, by
s
. This overload participates in overload resolution only if
s
is convertible to
typename std::common_type<Rep1, Rep2>::type
and
Rep2
is not a specialization of
duration
.
8) Converts the two durations to their common type and creates a duration whose tick count is the remainder of the tick counts after conversion.
Parameters
lhs | - | duration on the left-hand side of the operator |
rhs | - | duration on the right-hand side of the operator |
d | - | the duration argument for mixed-argument operators |
s | - | non-duration argument for mixed-argument operators |
Return value
Assuming that CD
is the function return type and CR<A, B> = std::common_type<A, B>::type
, then:
1)
CD(CD(lhs).count() + CD(rhs).count())
2)
CD(CD(lhs).count() - CD(rhs).count())
3-4)
CD(CD(d).count() * s)
5)
CD(CD(d).count() / s).
6)
CD(lhs).count() / CD(rhs).count()
(the return type of this operator is not a duration)
7)
CD(CD(d).count() % s)
8)
CD(CD(lhs).count() % CD(rhs).count())
Example
#include <chrono> #include <iostream> int main() { // simple arithmetic std::chrono::seconds s = std::chrono::hours(1) + 2*std::chrono::minutes(10) + std::chrono::seconds(70)/10; std::cout << "1 hour + 2*10 min + 70/10 sec = " << s.count() << " seconds\n"; // difference between dividing a duration by a number // and dividing a duration by another duration std::cout << "Dividing that by 2 minutes gives " << s / std::chrono::minutes(2) << '\n'; std::cout << "Dividing that by 2 gives " << (s / 2).count() << " seconds\n"; // the remainder operator is useful in determining where in a time // frame is this particular duration, e.g. to break it down into hours, // minutes, and seconds: std::cout << s.count() << " seconds is " << std::chrono::duration_cast<std::chrono::hours>( s ).count() << " hours, " << std::chrono::duration_cast<std::chrono::minutes>( s % std::chrono::hours(1) ).count() << " minutes, " << std::chrono::duration_cast<std::chrono::seconds>( s % std::chrono::minutes(1) ).count() << " seconds\n"; }
Output:
1 hour + 2*10 min + 70/10 sec = 4807 seconds Dividing that by 2 minutes gives 40 Dividing that by 2 gives 2403 seconds 4807 seconds is 1 hours, 20 minutes, 7 seconds
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 3050 | C++11 | convertibility constraint used non-const xvalue | use const lvalues instead |
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