xref: /llvm-project/libcxx/test/std/strings/basic.string/string.iterators/rbegin.pass.cpp (revision 6e1dcc9335116f650d68cdbed12bbb34a99b2d9b)
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 // <string>
10 
11 //       reverse_iterator rbegin(); // constexpr since C++20
12 // const_reverse_iterator rbegin() const; // constexpr since C++20
13 
14 #include <string>
15 #include <cassert>
16 
17 #include "test_macros.h"
18 #include "min_allocator.h"
19 
20 template <class S>
test(S s)21 TEST_CONSTEXPR_CXX20 void test(S s) {
22   const S& cs                           = s;
23   typename S::reverse_iterator b        = s.rbegin();
24   typename S::const_reverse_iterator cb = cs.rbegin();
25   if (!s.empty()) {
26     assert(*b == s.back());
27   }
28   assert(b == cb);
29 }
30 
31 template <class S>
test_string()32 TEST_CONSTEXPR_CXX20 void test_string() {
33   test(S());
34   test(S("123"));
35 }
36 
test()37 TEST_CONSTEXPR_CXX20 bool test() {
38   test_string<std::string>();
39 #if TEST_STD_VER >= 11
40   test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char> > >();
41 #endif
42 
43   return true;
44 }
45 
main(int,char **)46 int main(int, char**) {
47   test();
48 #if TEST_STD_VER > 17
49   static_assert(test());
50 #endif
51 
52   return 0;
53 }
54