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

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 <cassert>
#include <chrono>
#include <iostream>
 
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';
 
    wd = std::chrono::weekday{13};
    assert(!wd.ok());
    wd++;
    assert(wd.ok());
}

Output:

true true

See also

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

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