std::chrono::weekday::operator+=, std::chrono::weekday::operator-=
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std::chrono::weekday
Member functions
weekday::operator+=weekday::operator-=
Nonmember functions
Helper classes
(C++26)
constexpr std::chrono::weekday & operator+=( const std::chrono::days & d ) noexcept;
(1)
(since C++20)
constexpr std::chrono::weekday & operator-=( const std::chrono::days & d ) noexcept;
(2)
(since C++20)
Adds or subtracts d.count() from the weekday value, reducing the result modulo 7 to an integer in the range [0, 6].
1) Performs *this = *this + d;.
2) Performs *this = *this - d;.
Contents
[edit] Return value
A reference to this weekday after modification.
[edit] Notes
After a call to one of these functions, ok() is always true if no overflow occurred during the operation.
[edit] Example
Run this code
#include <chrono> #include <iostream> int main() { std::cout << std::boolalpha ; std::chrono::weekday wd{5}; // Friday is 5 wd += std::chrono::days (2); std::cout << (wd == std::chrono::weekday (0)) << ' ' << (wd == std::chrono::Sunday ) << ' '; wd -= std::chrono::days (3); std::cout << (wd == std::chrono::weekday (4)) << ' ' << (wd == std::chrono::Thursday ) << ' '; wd = std::chrono::Wednesday ; wd += std::chrono::days {8}; // ((3 += 8 == 11) % 7) == 4; std::cout << (wd == std::chrono::Thursday ) << ' '; wd -= (std::chrono::Sunday - std::chrono::Tuesday ); // -= -2 // (4 -= -2) == 6 std::cout << (wd == std::chrono::Saturday ) << '\n'; }
Output:
true true true true true true