std::chrono::month::operator+=, std::chrono::month::operator-=
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std::chrono::month
Member functions
month::operator+=month::operator-=
Nonmember functions
Helper classes
(C++26)
constexpr std::chrono::month & operator+=( const std::chrono::months & m ) noexcept;
(1)
(since C++20)
constexpr std::chrono::month & operator-=( const std::chrono::months & m ) noexcept;
(2)
(since C++20)
Adds or subtracts m.count() from the month value, reducing the result modulo 12 to an integer in the range [1, 12].
1) Performs *this = *this + m;.
2) Performs *this = *this - m;.
Contents
[edit] Return value
A reference to this month 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 <chrono> #include <iostream> int main() { std::cout << std::boolalpha ; std::chrono::month m{6}; m += std::chrono::months (2); std::cout << (m == std::chrono::month (8)) << ' ' << (m == std::chrono::August ) << ' '; m -= std::chrono::months (3); std::cout << (m == std::chrono::month (5)) << ' ' << (m == std::chrono::May ) << ' '; m = std::chrono::October ; m += std::chrono::months {8}; // ((10 += 8 == 18) % 12) == 6; std::cout << (m == std::chrono::June ) << ' '; m -= std::chrono::months {std::chrono::December - std::chrono::February }; // -= 10 // (6 -= 10) == -4; -4 % 12 == (12 - 4) == 8 std::cout << (m == std::chrono::August ) << '\n'; }
Output:
true true true true true true