1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <array>
// reference front(); // constexpr in C++17
// reference back(); // constexpr in C++17
// const_reference front(); // constexpr in C++14
// const_reference back(); // constexpr in C++14
#include <array>
#include <cassert>
#include "test_macros.h"
// std::array is explicitly allowed to be initialized with A a = { init-list };.
// Disable the missing braces warning for this reason.
#include "disable_missing_braces_warning.h"
#if TEST_STD_VER > 14
constexpr bool check_front( double val )
{
std::array<double, 3> arr = {1, 2, 3.5};
return arr.front() == val;
}
constexpr bool check_back( double val )
{
std::array<double, 3> arr = {1, 2, 3.5};
return arr.back() == val;
}
#endif
int main()
{
{
typedef double T;
typedef std::array<T, 3> C;
C c = {1, 2, 3.5};
C::reference r1 = c.front();
assert(r1 == 1);
r1 = 5.5;
assert(c[0] == 5.5);
C::reference r2 = c.back();
assert(r2 == 3.5);
r2 = 7.5;
assert(c[2] == 7.5);
}
{
typedef double T;
typedef std::array<T, 3> C;
const C c = {1, 2, 3.5};
C::const_reference r1 = c.front();
assert(r1 == 1);
C::const_reference r2 = c.back();
assert(r2 == 3.5);
}
#if TEST_STD_VER > 11
{
typedef double T;
typedef std::array<T, 3> C;
constexpr C c = {1, 2, 3.5};
constexpr T t1 = c.front();
static_assert (t1 == 1, "");
constexpr T t2 = c.back();
static_assert (t2 == 3.5, "");
}
#endif
#if TEST_STD_VER > 14
{
static_assert (check_front(1), "");
static_assert (check_back (3.5), "");
}
#endif
}
|
