NAME¶

std::chrono::year_month_weekday::operator+=,std::chrono::year_month_weekday::operator-= - std::chrono::year_month_weekday::operator+=,std::chrono::year_month_weekday::operator-=

Synopsis¶

constexpr std::chrono::year_month_weekday& (1) (since C++20)
operator+=( const std::chrono::years& dy ) const noexcept;
constexpr std::chrono::year_month_weekday& (2) (since C++20)
operator+=( const std::chrono::months& dm ) const noexcept;
constexpr std::chrono::year_month_weekday& (3) (since C++20)
operator-=( const std::chrono::years& dy ) const noexcept;
constexpr std::chrono::year_month_weekday& (4) (since C++20)
operator-=( const std::chrono::months& dm ) const noexcept;

Modifies the time point *this represents by the duration dy or dm.

1) Equivalent to *this = *this + dy;.
2) Equivalent to *this = *this + dm;.
3) Equivalent to *this = *this - dy;.
4) Equivalent to *this = *this - dm;.

For durations that are convertible to both std::chrono::years and
std::chrono::months, the years overloads (1,3) are preferred if the call would
otherwise be ambiguous.

Example¶

// Run this code

#include <cassert>
#include <chrono>
#include <iostream>

int main()
{
auto ymwi{1/std::chrono::Wednesday[2]/2021};
std::cout << ymwi << '\n';

ymwi += std::chrono::years(5);
std::cout << ymwi << '\n';
assert(static_cast<std::chrono::year_month_day>(ymwi) ==
std::chrono::year(2026)/1/14);

ymwi -= std::chrono::months(1);
std::cout << ymwi << '\n';
assert(static_cast<std::chrono::year_month_day>(ymwi) ==
std::chrono::day(10)/12/2025);
}

Output:¶

2021/Jan/Wed[2]
2026/Jan/Wed[2]
2025/Dec/Wed[2]

See also¶

operator+ adds or subtracts a year_month_weekday and some number of years or months
operator- (function)
(C++20)