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

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< cpp‎ | chrono‎ | month
 
 
Utilities library
General utilities
Date and time
Function objects
Formatting library (C++20)
(C++11)
Relational operators (deprecated in C++20)
Integer comparison functions
(C++20)(C++20)(C++20)   
(C++20)
Swap and type operations
(C++14)
(C++11)
(C++11)
(C++11)
(C++17)
Common vocabulary types
(C++11)
(C++17)
(C++17)
(C++17)
(C++11)
(C++17)
(C++23)
Elementary string conversions
(C++17)
(C++17)
 
 
 
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};

Parameters

(none)

Return value

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

Notes

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

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

See also

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