1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // <array>
10 
11 // reference operator[] (size_type)
12 // const_reference operator[] (size_type); // constexpr in C++14
13 // reference at (size_type)
14 // const_reference at (size_type); // constexpr in C++14
15 
16 #include <array>
17 #include <cassert>
18 
19 #ifndef TEST_HAS_NO_EXCEPTIONS
20 #include <stdexcept>
21 #endif
22 
23 #include "test_macros.h"
24 
25 // std::array is explicitly allowed to be initialized with A a = { init-list };.
26 // Disable the missing braces warning for this reason.
27 #include "disable_missing_braces_warning.h"
28 
29 #if TEST_STD_VER > 14
30 constexpr bool check_idx( size_t idx, double val )
31 {
32     std::array<double, 3> arr = {1, 2, 3.5};
33     return arr.at(idx) == val;
34 }
35 #endif
36 
37 int main(int, char**)
38 {
39     {
40         typedef double T;
41         typedef std::array<T, 3> C;
42         C c = {1, 2, 3.5};
43         C::reference r1 = c.at(0);
44         assert(r1 == 1);
45         r1 = 5.5;
46         assert(c.front() == 5.5);
47 
48         C::reference r2 = c.at(2);
49         assert(r2 == 3.5);
50         r2 = 7.5;
51         assert(c.back() == 7.5);
52 
53 #ifndef TEST_HAS_NO_EXCEPTIONS
54         try
55         {
56             TEST_IGNORE_NODISCARD  c.at(3);
57             assert(false);
58         }
59         catch (const std::out_of_range &) {}
60 #endif
61     }
62 #ifndef TEST_HAS_NO_EXCEPTIONS
63     {
64         typedef double T;
65         typedef std::array<T, 0> C;
66         C c = {};
67         C const& cc = c;
68         try
69         {
70             TEST_IGNORE_NODISCARD  c.at(0);
71             assert(false);
72         }
73         catch (const std::out_of_range &) {}
74         try
75         {
76             TEST_IGNORE_NODISCARD  cc.at(0);
77             assert(false);
78         }
79         catch (const std::out_of_range &) {}
80     }
81 #endif
82     {
83         typedef double T;
84         typedef std::array<T, 3> C;
85         const C c = {1, 2, 3.5};
86         C::const_reference r1 = c.at(0);
87         assert(r1 == 1);
88 
89         C::const_reference r2 = c.at(2);
90         assert(r2 == 3.5);
91 
92 #ifndef TEST_HAS_NO_EXCEPTIONS
93         try
94         {
95             TEST_IGNORE_NODISCARD  c.at(3);
96             assert(false);
97         }
98         catch (const std::out_of_range &) {}
99 #endif
100     }
101 
102 #if TEST_STD_VER > 11
103     {
104         typedef double T;
105         typedef std::array<T, 3> C;
106         constexpr C c = {1, 2, 3.5};
107 
108         constexpr T t1 = c.at(0);
109         static_assert (t1 == 1, "");
110 
111         constexpr T t2 = c.at(2);
112         static_assert (t2 == 3.5, "");
113     }
114 #endif
115 
116 #if TEST_STD_VER > 14
117     {
118         static_assert (check_idx(0, 1), "");
119         static_assert (check_idx(1, 2), "");
120         static_assert (check_idx(2, 3.5), "");
121     }
122 #endif
123 
124   return 0;
125 }
126