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); // constexpr in C++17
12// Libc++ marks it as noexcept
13
14#include <array>
15#include <cassert>
16
17#include "test_macros.h"
18
19TEST_CONSTEXPR_CXX17 bool tests()
20{
21 {
22 typedef double T;
23 typedef std::array<T, 3> C;
24 C c = {1, 2, 3.5};
25 LIBCPP_ASSERT_NOEXCEPT(c[0]);
26 ASSERT_SAME_TYPE(C::reference, decltype(c[0]));
27 C::reference r1 = c[0];
28 assert(r1 == 1);
29 r1 = 5.5;
30 assert(c.front() == 5.5);
31
32 C::reference r2 = c[2];
33 assert(r2 == 3.5);
34 r2 = 7.5;
35 assert(c.back() == 7.5);
36 }
37
38 // Test operator[] "works" on zero sized arrays
39 {
40 {
41 typedef double T;
42 typedef std::array<T, 0> C;
43 C c = {};
44 LIBCPP_ASSERT_NOEXCEPT(c[0]);
45 ASSERT_SAME_TYPE(C::reference, decltype(c[0]));
46 if (c.size() > (0)) { // always false
47 C::reference r = c[0];
48 (void)r;
49 }
50 }
51 {
52 typedef double T;
53 typedef std::array<const T, 0> C;
54 C c = {};
55 LIBCPP_ASSERT_NOEXCEPT(c[0]);
56 ASSERT_SAME_TYPE(C::reference, decltype(c[0]));
57 if (c.size() > (0)) { // always false
58 C::reference r = c[0];
59 (void)r;
60 }
61 }
62 }
63
64 return true;
65}
66
67int main(int, char**)
68{
69 tests();
70#if TEST_STD_VER >= 17
71 static_assert(tests(), "");
72#endif
73 return 0;
74}
75

source code of libcxx/test/std/containers/sequences/array/indexing.pass.cpp