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
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11
// <utility>
// exchange
// template<class T, class U=T>
// constexpr T // constexpr after C++17
// exchange(T& obj, U&& new_value);
#include <utility>
#include <cassert>
#include <string>
#include "test_macros.h"
#if TEST_STD_VER > 17
TEST_CONSTEXPR bool test_constexpr() {
int v = 12;
if (12 != std::exchange(v,23) || v != 23)
return false;
if (23 != std::exchange(v,static_cast<short>(67)) || v != 67)
return false;
if (67 != std::exchange<int, short>(v, {}) || v != 0)
return false;
return true;
}
#endif
int main(int, char**)
{
{
int v = 12;
assert ( std::exchange ( v, 23 ) == 12 );
assert ( v == 23 );
assert ( std::exchange ( v, static_cast<short>(67) ) == 23 );
assert ( v == 67 );
assert ((std::exchange<int, short> ( v, {} )) == 67 );
assert ( v == 0 );
}
{
bool b = false;
assert ( !std::exchange ( b, true ));
assert ( b );
}
{
const std::string s1 ( "Hi Mom!" );
const std::string s2 ( "Yo Dad!" );
std::string s3 = s1; // Mom
assert ( std::exchange ( s3, s2 ) == s1 );
assert ( s3 == s2 );
assert ( std::exchange ( s3, "Hi Mom!" ) == s2 );
assert ( s3 == s1 );
s3 = s2; // Dad
assert ( std::exchange ( s3, {} ) == s2 );
assert ( s3.size () == 0 );
s3 = s2; // Dad
assert ( std::exchange ( s3, "" ) == s2 );
assert ( s3.size () == 0 );
}
#if TEST_STD_VER > 17
static_assert(test_constexpr());
#endif
return 0;
}
|
