decrement.pass.cpp (1426B)
1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 10 11 // <chrono> 12 // class day; 13 14 // constexpr day& operator--() noexcept; 15 // constexpr day operator--(int) noexcept; 16 17 18 #include <chrono> 19 #include <type_traits> 20 #include <cassert> 21 22 #include "test_macros.h" 23 24 template <typename D> 25 constexpr bool testConstexpr() 26 { 27 D d1{10}; 28 if (static_cast<unsigned>(--d1) != 9) return false; 29 if (static_cast<unsigned>(d1--) != 9) return false; 30 if (static_cast<unsigned>(d1) != 8) return false; 31 return true; 32 } 33 34 int main() 35 { 36 using day = std::chrono::day; 37 ASSERT_NOEXCEPT(--(std::declval<day&>()) ); 38 ASSERT_NOEXCEPT( (std::declval<day&>())--); 39 40 ASSERT_SAME_TYPE(day , decltype( std::declval<day&>()--)); 41 ASSERT_SAME_TYPE(day&, decltype(--std::declval<day&>() )); 42 43 static_assert(testConstexpr<day>(), ""); 44 45 for (unsigned i = 10; i <= 20; ++i) 46 { 47 day day(i); 48 assert(static_cast<unsigned>(--day) == i - 1); 49 assert(static_cast<unsigned>(day--) == i - 1); 50 assert(static_cast<unsigned>(day) == i - 2); 51 } 52 }