std::chrono::weekday::operator++, std::chrono::weekday::operator--

< cpp‎ | chrono‎ | weekday
constexpr std::chrono::weekday& operator++() noexcept;
 (1) (since C++20)
constexpr std::chrono::weekday operator++(int) noexcept;
 (2) (since C++20)
constexpr std::chrono::weekday& operator--() noexcept;
 (3) (since C++20)
constexpr std::chrono::weekday operator--(int) noexcept;
 (4) (since C++20)

Adds or subtracts 1 from the weekday value, reducing the result modulo 7 to an integer in the range [0, 6].

1-2) Performs *this += std::chrono::days{1};
3-4) Performs *this -= std::chrono::days{1};

Parameters

(none)

Return value

1,3) a reference to this weekday after modification
2,4) a copy of the weekday made before modification

Notes

After a call to one of these functions, ok() is always true.

Example

#include <iostream>
#include <chrono>
 
int main()
{
    std::cout << std::boolalpha;
 
    std::chrono::weekday wd {0}; // Sunday is 0 or 7
 
    --wd;
    std::cout << (wd == std::chrono::Saturday) << ' ';
 
    ++wd;
    std::cout << (wd == std::chrono::Sunday) << '\n';
}

Output:

true true

See also

 adds or subtracts a number of days
(public member function)
(C++20)
 performs arithmetic on weekdays
(function)