1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// UNSUPPORTED: c++03, c++11, c++14, c++17
9
10// <chrono>
11// class month;
12
13// constexpr month operator+(const month& x, const months& y) noexcept;
14// Returns: month(int{x} + y.count()).
15//
16// constexpr month operator+(const months& x, const month& y) noexcept;
17// Returns:
18// month{modulo(static_cast<long long>(int{x}) + (y.count() - 1), 12) + 1}
19// where modulo(n, 12) computes the remainder of n divided by 12 using Euclidean division.
20// [Note: Given a divisor of 12, Euclidean division truncates towards negative infinity
21// and always produces a remainder in the range of [0, 11].
22// Assuming no overflow in the signed summation, this operation results in a month
23// holding a value in the range [1, 12] even if !x.ok(). -end note]
24// [Example: February + months{11} == January. -end example]
25
26#include <chrono>
27#include <cassert>
28#include <type_traits>
29#include <utility>
30
31#include "test_macros.h"
32
33constexpr bool test() {
34 using month = std::chrono::month;
35 using months = std::chrono::months;
36
37 month my{2};
38 for (unsigned i = 0; i <= 15; ++i) {
39 month m1 = my + months{i};
40 month m2 = months{i} + my;
41 assert(m1.ok());
42 assert(m2.ok());
43 assert(m1 == m2);
44 unsigned exp = i + 2;
45 while (exp > 12)
46 exp -= 12;
47 assert(static_cast<unsigned>(m1) == exp);
48 assert(static_cast<unsigned>(m2) == exp);
49 }
50
51 return true;
52}
53
54int main(int, char**) {
55 using month = std::chrono::month;
56 using months = std::chrono::months;
57
58 ASSERT_NOEXCEPT(std::declval<month>() + std::declval<months>());
59 ASSERT_NOEXCEPT(std::declval<months>() + std::declval<month>());
60
61 ASSERT_SAME_TYPE(month, decltype(std::declval<month>() + std::declval<months>()));
62 ASSERT_SAME_TYPE(month, decltype(std::declval<months>() + std::declval<month>()));
63
64 test();
65 static_assert(test());
66
67 return 0;
68}
69

source code of libcxx/test/std/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp