ctor.sys_days.pass.cpp (2027B)
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 weekday; 13 14 // constexpr weekday(const sys_days& dp) noexcept; 15 // 16 // Effects: Constructs an object of type weekday by computing what day 17 // of the week corresponds to the sys_days dp, and representing 18 // that day of the week in wd_ 19 // 20 // Remarks: For any value ymd of type year_month_day for which ymd.ok() is true, 21 // ymd == year_month_day{sys_days{ymd}} is true. 22 // 23 // [Example: 24 // If dp represents 1970-01-01, the constructed weekday represents Thursday by storing 4 in wd_. 25 // —end example] 26 27 #include <chrono> 28 #include <type_traits> 29 #include <cassert> 30 31 #include "test_macros.h" 32 33 int main() 34 { 35 using sys_days = std::chrono::sys_days; 36 using days = std::chrono::days; 37 using weekday = std::chrono::weekday; 38 39 ASSERT_NOEXCEPT(weekday{std::declval<sys_days>()}); 40 41 { 42 constexpr sys_days sd{}; // 1-Jan-1970 was a Thursday 43 constexpr weekday wd{sd}; 44 45 static_assert( wd.ok(), ""); 46 static_assert(static_cast<unsigned>(wd) == 4, ""); 47 } 48 49 { 50 constexpr sys_days sd{days{10957+32}}; // 2-Feb-2000 was a Wednesday 51 constexpr weekday wd{sd}; 52 53 static_assert( wd.ok(), ""); 54 static_assert(static_cast<unsigned>(wd) == 3, ""); 55 } 56 57 58 { 59 constexpr sys_days sd{days{-10957}}; // 2-Jan-1940 was a Tuesday 60 constexpr weekday wd{sd}; 61 62 static_assert( wd.ok(), ""); 63 static_assert(static_cast<unsigned>(wd) == 2, ""); 64 } 65 66 { 67 sys_days sd{days{-(10957+34)}}; // 29-Nov-1939 was a Wednesday 68 weekday wd{sd}; 69 70 assert( wd.ok()); 71 assert(static_cast<unsigned>(wd) == 3); 72 } 73 }