decrement.pass.cpp (1461B)
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 month; 13 14 // constexpr month& operator--() noexcept; 15 // constexpr month 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 M> 25 constexpr bool testConstexpr() 26 { 27 M m1{10}; 28 if (static_cast<unsigned>(--m1) != 9) return false; 29 if (static_cast<unsigned>(m1--) != 9) return false; 30 if (static_cast<unsigned>(m1) != 8) return false; 31 return true; 32 } 33 34 int main() 35 { 36 using month = std::chrono::month; 37 38 ASSERT_NOEXCEPT(--(std::declval<month&>()) ); 39 ASSERT_NOEXCEPT( (std::declval<month&>())--); 40 41 ASSERT_SAME_TYPE(month , decltype( std::declval<month&>()--)); 42 ASSERT_SAME_TYPE(month&, decltype(--std::declval<month&>() )); 43 44 static_assert(testConstexpr<month>(), ""); 45 46 for (unsigned i = 10; i <= 20; ++i) 47 { 48 month month(i); 49 assert(static_cast<unsigned>(--month) == i - 1); 50 assert(static_cast<unsigned>(month--) == i - 1); 51 assert(static_cast<unsigned>(month) == i - 2); 52 } 53 }