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 // template <RandomAccessIterator Iter1, RandomAccessIterator Iter2>
15 //   requires HasMinus<Iter2, Iter1>
16 //   auto operator-(const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y)
17 //   -> decltype(y.base() - x.base());
18 
19 #include <iterator>
20 #include <cstddef>
21 #include <cassert>
22 
23 #include "test_iterators.h"
24 
25 template <class It1, class It2>
26 void
test(It1 l,It2 r,std::ptrdiff_t x)27 test(It1 l, It2 r, std::ptrdiff_t x)
28 {
29     const std::reverse_iterator<It1> r1(l);
30     const std::reverse_iterator<It2> r2(r);
31     assert((r1 - r2) == x);
32 }
33 
main()34 int main()
35 {
36     char s[3] = {0};
37     test(random_access_iterator<const char*>(s), random_access_iterator<char*>(s), 0);
38     test(random_access_iterator<char*>(s), random_access_iterator<const char*>(s+1), 1);
39     test(random_access_iterator<const char*>(s+1), random_access_iterator<char*>(s), -1);
40     test(s, s, 0);
41     test(s, s+1, 1);
42     test(s+1, s, -1);
43 }
44