std::chrono::weekday::operator+=, std::chrono::weekday::operator-= - cppreference.com (original) (raw)

C++

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Date and time library

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std::chrono::weekday

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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

• 1 Return value
• 2 Notes
• 3 Example
• 4 See also

[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 #include   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

[edit] See also