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 // <iterator>
10
11 // reverse_iterator
12
13 // requires RandomAccessIterator<Iter>
14 // unspecified operator[](difference_type n) const; // constexpr since C++17
15
16 #include <iterator>
17 #include <cassert>
18
19 #include "test_macros.h"
20 #include "test_iterators.h"
21
22 template <class It>
test(It i,typename std::iterator_traits<It>::difference_type n,typename std::iterator_traits<It>::value_type x)23 TEST_CONSTEXPR_CXX17 void test(It i,
24 typename std::iterator_traits<It>::difference_type n,
25 typename std::iterator_traits<It>::value_type x) {
26 typedef typename std::iterator_traits<It>::value_type value_type;
27 const std::reverse_iterator<It> r(i);
28 value_type rr = r[n];
29 assert(rr == x);
30 }
31
tests()32 TEST_CONSTEXPR_CXX17 bool tests() {
33 const char* s = "1234567890";
34 test(random_access_iterator<const char*>(s+5), 4, '1');
35 test(random_access_iterator<const char*>(s+5), 0, '5');
36 test(s+5, 4, '1');
37 test(s+5, 0, '5');
38 return true;
39 }
40
main(int,char **)41 int main(int, char**) {
42 tests();
43 #if TEST_STD_VER > 14
44 static_assert(tests(), "");
45 #endif
46 return 0;
47 }
48