std::chrono::year::operator++, std::chrono::year::operator--

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

Adds or subtracts 1 from the year value.

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

Parameters

(none)

Return value

1,3) A reference to this year after modification.
2,4) A copy of the year made before modification.

Notes

If the result would be outside the range [-32767, 32767], the actual stored value is unspecified.

Example

#include <chrono>
#include <iostream>
 
int main()
{
    std::cout << std::boolalpha;
 
    std::chrono::year y{2020};
    std::cout << (++y == std::chrono::year(2021)) << ' ';
    std::cout << (--y == std::chrono::year(2020)) << '\n';
 
    using namespace std::literals::chrono_literals;
    y = 32767y;
    y++; //← unspecified, see ↑ Notes ↑
    std::cout << static_cast<int>(y) << '\n';
}

Possible output:

true true
-32768

See also

adds or subtracts a number of years from a year
(public member function)
(C++20)
 performs arithmetic on years
(function)

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/chrono/year/operator_inc_dec