xref: /llvm-project/libcxx/test/std/containers/sequences/array/indexing.pass.cpp (revision a730ed31491b32b2b3b9c1a08bcd915b9b7cd167)
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 operator[] (size_type)
13 // const_reference operator[] (size_type); // constexpr in C++14
14 // reference at (size_type)
15 // const_reference at (size_type); // 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_idx( size_t idx, double val )
28 {
29     std::array<double, 3> arr = {1, 2, 3.5};
30 	return arr[idx] == val;
31 }
32 #endif
33 
34 int main()
35 {
36     {
37         typedef double T;
38         typedef std::array<T, 3> C;
39         C c = {1, 2, 3.5};
40         C::reference r1 = c[0];
41         assert(r1 == 1);
42         r1 = 5.5;
43         assert(c.front() == 5.5);
44 
45         C::reference r2 = c[2];
46         assert(r2 == 3.5);
47         r2 = 7.5;
48         assert(c.back() == 7.5);
49     }
50     {
51         typedef double T;
52         typedef std::array<T, 3> C;
53         const C c = {1, 2, 3.5};
54         C::const_reference r1 = c[0];
55         assert(r1 == 1);
56         C::const_reference r2 = c[2];
57         assert(r2 == 3.5);
58     }
59 
60 #if TEST_STD_VER > 11
61     {
62         typedef double T;
63         typedef std::array<T, 3> C;
64         constexpr C c = {1, 2, 3.5};
65 
66         constexpr T t1 = c[0];
67         static_assert (t1 == 1, "");
68 
69         constexpr T t2 = c[2];
70         static_assert (t2 == 3.5, "");
71     }
72 #endif
73 
74 #if TEST_STD_VER > 14
75     {
76         static_assert (check_idx(0, 1), "");
77         static_assert (check_idx(1, 2), "");
78         static_assert (check_idx(2, 3.5), "");
79     }
80 #endif
81 }
82