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 10 // <array> 11 12 // reference front(); // constexpr in C++17 13 // reference back(); // constexpr in C++17 14 // const_reference front(); // constexpr in C++14 15 // const_reference back(); // constexpr in C++14 16 17 #include <array> 18 #include <cassert> 19 20 #include "test_macros.h" 21 22 // std::array is explicitly allowed to be initialized with A a = { init-list };. 23 // Disable the missing braces warning for this reason. 24 #include "disable_missing_braces_warning.h" 25 26 #if TEST_STD_VER > 14 27 constexpr bool check_front( double val ) 28 { 29 std::array<double, 3> arr = {1, 2, 3.5}; 30 return arr.front() == val; 31 } 32 33 constexpr bool check_back( double val ) 34 { 35 std::array<double, 3> arr = {1, 2, 3.5}; 36 return arr.back() == val; 37 } 38 #endif 39 40 int main() 41 { 42 { 43 typedef double T; 44 typedef std::array<T, 3> C; 45 C c = {1, 2, 3.5}; 46 47 C::reference r1 = c.front(); 48 assert(r1 == 1); 49 r1 = 5.5; 50 assert(c[0] == 5.5); 51 52 C::reference r2 = c.back(); 53 assert(r2 == 3.5); 54 r2 = 7.5; 55 assert(c[2] == 7.5); 56 } 57 { 58 typedef double T; 59 typedef std::array<T, 3> C; 60 const C c = {1, 2, 3.5}; 61 C::const_reference r1 = c.front(); 62 assert(r1 == 1); 63 64 C::const_reference r2 = c.back(); 65 assert(r2 == 3.5); 66 } 67 { 68 typedef double T; 69 typedef std::array<T, 0> C; 70 C c = {}; 71 C const& cc = c; 72 static_assert((std::is_same<decltype(c.front()), T &>::value), ""); 73 static_assert((std::is_same<decltype(cc.front()), const T &>::value), ""); 74 static_assert((std::is_same<decltype(c.back()), T &>::value), ""); 75 static_assert((std::is_same<decltype(cc.back()), const T &>::value), ""); 76 if (c.size() > (0)) { // always false 77 TEST_IGNORE_NODISCARD c.front(); 78 TEST_IGNORE_NODISCARD c.back(); 79 TEST_IGNORE_NODISCARD cc.front(); 80 TEST_IGNORE_NODISCARD cc.back(); 81 } 82 } 83 { 84 typedef double T; 85 typedef std::array<const T, 0> C; 86 C c = {{}}; 87 C const& cc = c; 88 static_assert((std::is_same<decltype(c.front()), const T &>::value), ""); 89 static_assert((std::is_same<decltype(cc.front()), const T &>::value), ""); 90 static_assert((std::is_same<decltype(c.back()), const T &>::value), ""); 91 static_assert((std::is_same<decltype(cc.back()), const T &>::value), ""); 92 if (c.size() > (0)) { 93 TEST_IGNORE_NODISCARD c.front(); 94 TEST_IGNORE_NODISCARD c.back(); 95 TEST_IGNORE_NODISCARD cc.front(); 96 TEST_IGNORE_NODISCARD cc.back(); 97 } 98 } 99 #if TEST_STD_VER > 11 100 { 101 typedef double T; 102 typedef std::array<T, 3> C; 103 constexpr C c = {1, 2, 3.5}; 104 105 constexpr T t1 = c.front(); 106 static_assert (t1 == 1, ""); 107 108 constexpr T t2 = c.back(); 109 static_assert (t2 == 3.5, ""); 110 } 111 #endif 112 113 #if TEST_STD_VER > 14 114 { 115 static_assert (check_front(1), ""); 116 static_assert (check_back (3.5), ""); 117 } 118 #endif 119 } 120
