# std::chrono::operator+, std::chrono::operator- (std::chrono::day)

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< cpp‎ | chrono‎ | day

constexpr std::chrono::day operator+(const std::chrono::day & d, const std::chrono::days & ds) noexcept; | (1) | (since C++20)
constexpr std::chrono::day operator+(const std::chrono::days & ds, const std::chrono::day & d) noexcept; | (2) | (since C++20)
constexpr std::chrono::day operator-(const std::chrono::day & d, const std::chrono::days & ds) noexcept; | (3) | (since C++20)
constexpr std::chrono::days operator-(const std::chrono::day & x, const std::chrono::day & y) noexcept; | (4) | (since C++20)

1-2) Adds ds.count() days to `d`.
3) Subtracts ds.count() days from `d`.
4) Calculate the difference, in days, between two `day` `x` and `y`.

### Return value

1-2) std::chrono::day (unsigned(d) + ds.count())
3) std::chrono::day (unsigned(d) - ds.count())
4) std::chrono::days (int(unsigned(x)) - int(unsigned(y)))

### Notes

For (1-3), if the result would be outside the range [0, 255], the actual stored value is unspecified.

### Example

| This section is incomplete Reason: no example

### See also

operator++operator++(int)operator--operator--(int) | increments or decrements the day (public member function)
operator+=operator-= | adds or subtracts a number of days (public member function)

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