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// <iterator>
11
12// reverse_iterator
13
14// requires RandomAccessIterator<Iter>
15//   unspecified operator[](difference_type n) const;
16
17#include <iterator>
18#include <cassert>
19
20#include "test_macros.h"
21#include "test_iterators.h"
22
23template <class It>
24void
25test(It i, typename std::iterator_traits<It>::difference_type n,
26     typename std::iterator_traits<It>::value_type x)
27{
28    typedef typename std::iterator_traits<It>::value_type value_type;
29    const std::reverse_iterator<It> r(i);
30    value_type rr = r[n];
31    assert(rr == x);
32}
33
34int main()
35{
36    const char* s = "1234567890";
37    test(random_access_iterator<const char*>(s+5), 4, '1');
38    test(s+5, 4, '1');
39
40#if TEST_STD_VER > 14
41    {
42    constexpr const char *p = "123456789";
43    typedef std::reverse_iterator<const char *> RI;
44    constexpr RI it1 = std::make_reverse_iterator(p + 5);
45    static_assert(it1[0] == '5', "");
46    static_assert(it1[4] == '1', "");
47    }
48#endif
49}
50