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 // template <InputIterator Iter>
12 //   Iter::difference_type
13 //   distance(Iter first, Iter last);
14 //
15 // template <RandomAccessIterator Iter>
16 //   Iter::difference_type
17 //   distance(Iter first, Iter last);
18 
19 #include <iterator>
20 #include <cassert>
21 
22 #include "test_iterators.h"
23 
24 template <class It>
25 void
26 test(It first, It last, typename std::iterator_traits<It>::difference_type x)
27 {
28     assert(std::distance(first, last) == x);
29 }
30 
31 #if TEST_STD_VER > 14
32 template <class It>
33 constexpr bool
34 constexpr_test(It first, It last, typename std::iterator_traits<It>::difference_type x)
35 {
36     return std::distance(first, last) == x;
37 }
38 #endif
39 
40 int main(int, char**)
41 {
42     {
43     const char* s = "1234567890";
44     test(input_iterator<const char*>(s), input_iterator<const char*>(s+10), 10);
45     test(forward_iterator<const char*>(s), forward_iterator<const char*>(s+10), 10);
46     test(bidirectional_iterator<const char*>(s), bidirectional_iterator<const char*>(s+10), 10);
47     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s+10), 10);
48     test(s, s+10, 10);
49     }
50 #if TEST_STD_VER > 14
51     {
52     constexpr const char* s = "1234567890";
53     static_assert( constexpr_test(input_iterator<const char*>(s), input_iterator<const char*>(s+10), 10), "");
54     static_assert( constexpr_test(forward_iterator<const char*>(s), forward_iterator<const char*>(s+10), 10), "");
55     static_assert( constexpr_test(bidirectional_iterator<const char*>(s), bidirectional_iterator<const char*>(s+10), 10), "");
56     static_assert( constexpr_test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s+10), 10), "");
57     static_assert( constexpr_test(s, s+10, 10), "");
58     }
59 #endif
60 
61   return 0;
62 }
63