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 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
10 
11 // <string>
12 
13 //   bool starts_with(const CharT *x) const;
14 
15 #include <string>
16 #include <cassert>
17 
18 #include "test_macros.h"
19 
20 int main()
21 {
22     {
23     typedef std::string S;
24     const char *s = "abcde";
25     S  s0 {};
26     S  s1 { s, 1 };
27     S  s2 { s, 2 };
28 //     S  s3 { s, 3 };
29 //     S  s4 { s, 4 };
30 //     S  s5 { s, 5 };
31     S  sNot {"def", 3 };
32 
33     LIBCPP_ASSERT_NOEXCEPT(s0.starts_with(""));
34 
35     assert ( s0.starts_with(""));
36     assert (!s0.starts_with("a"));
37 
38     assert ( s1.starts_with(""));
39     assert ( s1.starts_with("a"));
40     assert (!s1.starts_with("ab"));
41     assert (!s1.starts_with("abc"));
42     assert (!s1.starts_with("abcd"));
43     assert (!s1.starts_with("abcde"));
44     assert (!s1.starts_with("def"));
45 
46     assert ( s2.starts_with(""));
47     assert ( s2.starts_with("a"));
48     assert ( s2.starts_with("ab"));
49     assert (!s2.starts_with("abc"));
50     assert (!s2.starts_with("abcd"));
51     assert (!s2.starts_with("abcde"));
52     assert (!s2.starts_with("def"));
53 
54     assert ( sNot.starts_with(""));
55     assert (!sNot.starts_with("a"));
56     assert (!sNot.starts_with("ab"));
57     assert (!sNot.starts_with("abc"));
58     assert (!sNot.starts_with("abcd"));
59     assert (!sNot.starts_with("abcde"));
60     assert ( sNot.starts_with("def"));
61     }
62 }
63