libcxx/test/std/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp

   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--() noexcept;
  14 //  constexpr month operator--(int) noexcept;
  15
  16 #include <chrono>
  17 #include <type_traits>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21
  22 constexpr bool test() {
  23   using month = std::chrono::month;
  24   for (unsigned i = 0; i <= 15; ++i) {
  25     month m1(i);
  26     month m2 = m1--;
  27     assert(m1.ok());
  28     assert(m1 != m2);
  29
  30     unsigned exp = i == 0 ? 11 : i == 1 ? 12 : i - 1;
  31     while (exp > 12)
  32       exp -= 12;
  33     assert(static_cast<unsigned>(m1) == exp);
  34   }
  35   for (unsigned i = 0; i <= 15; ++i) {
  36     month m1(i);
  37     month m2 = --m1;
  38     assert(m1.ok());
  39     assert(m2.ok());
  40     assert(m1 == m2);
  41
  42     unsigned exp = i == 0 ? 11 : i == 1 ? 12 : i - 1;
  43     while (exp > 12)
  44       exp -= 12;
  45     assert(static_cast<unsigned>(m1) == exp);
  46   }
  47
  48   return true;
  49 }
  50
  51 int main(int, char**) {
  52   using month = std::chrono::month;
  53
  54   ASSERT_NOEXCEPT(--(std::declval<month&>()));
  55   ASSERT_NOEXCEPT((std::declval<month&>())--);
  56
  57   ASSERT_SAME_TYPE(month, decltype(std::declval<month&>()--));
  58   ASSERT_SAME_TYPE(month&, decltype(--std::declval<month&>()));
  59
  60   test();
  61   static_assert(test());
  62
  63   return 0;
  64 }