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libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp

53 lines
1.4 KiB
C++

//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// <chrono>
// class day;
// constexpr day& operator--() noexcept;
// constexpr day operator--(int) noexcept;
#include <chrono>
#include <type_traits>
#include <cassert>
#include "test_macros.h"
template <typename D>
constexpr bool testConstexpr()
{
D d1{10};
if (static_cast<unsigned>(--d1) != 9) return false;
if (static_cast<unsigned>(d1--) != 9) return false;
if (static_cast<unsigned>(d1) != 8) return false;
return true;
}
int main()
{
using day = std::chrono::day;
ASSERT_NOEXCEPT(--(std::declval<day&>()) );
ASSERT_NOEXCEPT( (std::declval<day&>())--);
ASSERT_SAME_TYPE(day , decltype( std::declval<day&>()--));
ASSERT_SAME_TYPE(day&, decltype(--std::declval<day&>() ));
static_assert(testConstexpr<day>(), "");
for (unsigned i = 10; i <= 20; ++i)
{
day day(i);
assert(static_cast<unsigned>(--day) == i - 1);
assert(static_cast<unsigned>(day--) == i - 1);
assert(static_cast<unsigned>(day) == i - 2);
}
}