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

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