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// UNSUPPORTED: c++03, c++11, c++14, c++17
10
11// friend constexpr iter_difference_t<W> operator-(const iterator& x, const sentinel& y)
12// requires sized_sentinel_for<Bound, W>;
13// friend constexpr iter_difference_t<W> operator-(const sentinel& x, const iterator& y)
14// requires sized_sentinel_for<Bound, W>;
15
16#include <ranges>
17#include <cassert>
18
19#include "test_macros.h"
20#include "test_iterators.h"
21#include "../types.h"
22
23template<class T>
24concept MinusInvocable = requires(std::ranges::iota_view<T, IntSentinelWith<T>> io) {
25 io.end() - io.begin();
26};
27
28constexpr bool test() {
29 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
30
31 {
32 auto outIter = random_access_iterator<int*>(buffer);
33 std::ranges::iota_view<random_access_iterator<int*>, IntSentinelWith<random_access_iterator<int*>>> io(
34 outIter, IntSentinelWith<random_access_iterator<int*>>(std::ranges::next(outIter, 8)));
35 auto iter = io.begin();
36 auto sent = io.end();
37 assert(iter - sent == -8);
38 assert(sent - iter == 8);
39 }
40 {
41 auto outIter = random_access_iterator<int*>(buffer);
42 const std::ranges::iota_view<random_access_iterator<int*>, IntSentinelWith<random_access_iterator<int*>>> io(
43 outIter, IntSentinelWith<random_access_iterator<int*>>(std::ranges::next(outIter, 8)));
44 const auto iter = io.begin();
45 const auto sent = io.end();
46 assert(iter - sent == -8);
47 assert(sent - iter == 8);
48 }
49
50 {
51 // The minus operator requires that "W" is an input_or_output_iterator.
52 static_assert(!MinusInvocable<int>);
53 }
54
55 return true;
56}
57
58int main(int, char**) {
59 test();
60 static_assert(test());
61
62 return 0;
63}
64

source code of libcxx/test/std/ranges/range.factories/range.iota.view/sentinel/minus.pass.cpp