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libcxx_old/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp

55 lines
1.5 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// <chrono>
// class month;
// constexpr month& operator--() noexcept;
// constexpr month operator--(int) noexcept;
#include <chrono>
#include <type_traits>
#include <cassert>
#include "test_macros.h"
template <typename M>
constexpr bool testConstexpr()
{
M m1{10};
if (static_cast<unsigned>(--m1) != 9) return false;
if (static_cast<unsigned>(m1--) != 9) return false;
if (static_cast<unsigned>(m1) != 8) return false;
return true;
}
int main(int, char**)
{
using month = std::chrono::month;
ASSERT_NOEXCEPT(--(std::declval<month&>()) );
ASSERT_NOEXCEPT( (std::declval<month&>())--);
ASSERT_SAME_TYPE(month , decltype( std::declval<month&>()--));
ASSERT_SAME_TYPE(month&, decltype(--std::declval<month&>() ));
static_assert(testConstexpr<month>(), "");
for (unsigned i = 10; i <= 20; ++i)
{
month month(i);
assert(static_cast<unsigned>(--month) == i - 1);
assert(static_cast<unsigned>(month--) == i - 1);
assert(static_cast<unsigned>(month) == i - 2);
}
return 0;
}