1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// utilities
11
12// exchange
13
14#include <utility>
15#include <cassert>
16#include <string>
17
18int main()
19{
20#if _LIBCPP_STD_VER > 11
21    {
22    int v = 12;
23    assert ( std::exchange ( v, 23 ) == 12 );
24    assert ( v == 23 );
25    assert ( std::exchange ( v, 67.2 ) == 23 );
26    assert ( v == 67 );
27
28    assert ((std::exchange<int, float> ( v, {} )) == 67 );
29    assert ( v == 0 );
30
31    }
32
33    {
34    bool b = false;
35    assert ( !std::exchange ( b, true ));
36    assert ( b );
37    }
38
39    {
40    const std::string s1 ( "Hi Mom!" );
41    const std::string s2 ( "Yo Dad!" );
42    std::string s3 = s1; // Mom
43    assert ( std::exchange ( s3, s2 ) == s1 );
44    assert ( s3 == s2 );
45    assert ( std::exchange ( s3, "Hi Mom!" ) == s2 );
46    assert ( s3 == s1 );
47
48    s3 = s2; // Dad
49    assert ( std::exchange ( s3, {} ) == s2 );
50    assert ( s3.size () == 0 );
51
52    s3 = s2; // Dad
53    assert ( std::exchange ( s3, "" ) == s2 );
54    assert ( s3.size () == 0 );
55    }
56
57#endif
58}
59