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// const_reference front() const; // constexpr in C++14
12// const_reference back() const; // constexpr in C++14
13
14#include <array>
15#include <cassert>
16
17#include "test_macros.h"
18
19TEST_CONSTEXPR_CXX14 bool tests()
20{
21 {
22 typedef double T;
23 typedef std::array<T, 3> C;
24 C const c = {1, 2, 3.5};
25 C::const_reference r1 = c.front();
26 assert(r1 == 1);
27
28 C::const_reference r2 = c.back();
29 assert(r2 == 3.5);
30 }
31 {
32 typedef double T;
33 typedef std::array<T, 0> C;
34 C const c = {};
35 ASSERT_SAME_TYPE(decltype(c.back()), C::const_reference);
36 LIBCPP_ASSERT_NOEXCEPT(c.back());
37 ASSERT_SAME_TYPE(decltype(c.front()), C::const_reference);
38 LIBCPP_ASSERT_NOEXCEPT(c.front());
39 if (c.size() > (0)) { // always false
40 TEST_IGNORE_NODISCARD c.front();
41 TEST_IGNORE_NODISCARD c.back();
42 }
43 }
44 {
45 typedef double T;
46 typedef std::array<const T, 0> C;
47 C const c = {};
48 ASSERT_SAME_TYPE(decltype(c.back()), C::const_reference);
49 LIBCPP_ASSERT_NOEXCEPT(c.back());
50 ASSERT_SAME_TYPE(decltype(c.front()), C::const_reference);
51 LIBCPP_ASSERT_NOEXCEPT(c.front());
52 if (c.size() > (0)) {
53 TEST_IGNORE_NODISCARD c.front();
54 TEST_IGNORE_NODISCARD c.back();
55 }
56 }
57
58 return true;
59}
60
61int main(int, char**)
62{
63 tests();
64#if TEST_STD_VER >= 14
65 static_assert(tests(), "");
66#endif
67 return 0;
68}
69

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