libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.prev/iterator.pass.cpp

   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 // ranges::prev(it)
  12
  13 #include <iterator>
  14 #include <cassert>
  15
  16 #include "test_iterators.h"
  17
  18 template <class It>
  19 constexpr void check(int* first, int* expected) {
  20   It it(first);
  21   std::same_as<It> auto result = std::ranges::prev(std::move(it));
  22   assert(base(result) == expected);
  23 }
  24
  25 constexpr bool test() {
  26   int range[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
  27
  28   for (int n = 1; n != 10; ++n) {
  29     check<bidirectional_iterator<int*>>(range+n, range+n-1);
  30     check<random_access_iterator<int*>>(range+n, range+n-1);
  31     check<contiguous_iterator<int*>>(   range+n, range+n-1);
  32     check<int*>(                        range+n, range+n-1);
  33   }
  34
  35   return true;
  36 }
  37
  38
  39 int main(int, char**) {
  40   test();
  41   static_assert(test());
  42   return 0;
  43 }