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std::chrono::month::operator++, std::chrono::month::operator--

From cppreference.com
< cpp‎ | chrono‎ | month
 
 
Utilities library
General utilities
Date and time
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constexpr std::chrono::month& operator++() noexcept;
(1) (since C++20)
constexpr std::chrono::month operator++(int) noexcept;
(2) (since C++20)
constexpr std::chrono::month& operator--() noexcept;
(3) (since C++20)
constexpr std::chrono::month operator--(int) noexcept;
(4) (since C++20)

Adds or subtracts 1 from the month value, reducing the result modulo 12 to an integer in the range [1, 12].

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

Contents

[edit] Parameters

(none)

[edit] Return value

1,3) a reference to this month after modification
2,4) a copy of the month made before modification

[edit] Notes

After a call to one of these functions, ok() is always true.

[edit] Example

#include <cassert>
#include <iostream>
#include <chrono>
 
int main()
{
    std::chrono::month m {6};
 
    ++m;
    assert(m == std::chrono::month(7));
 
    --m;
    assert(m == std::chrono::month(6));
 
    m = std::chrono::December;
    m++; // rounds up to January
    assert(m.ok());
    std::cout << unsigned(m) << '\n';
 
    m = std::chrono::January;
    m--; // rounds down to December
    assert(m.ok());
    std::cout << unsigned(m) << '\n';
}

Output:

1
12

[edit] See also

adds or subtracts a number of months
(public member function) [edit]
performs arithmetic on months
(function) [edit]