libstdc++-v3/testsuite/25_algorithms/fold_right/1.cc

   1 // { dg-do run { target c++23 } }
   2
   3 #include <algorithm>
   4 #include <ranges>
   5 #include <testsuite_iterators.h>
   6
   7 namespace ranges = std::ranges;
   8 namespace views = std::views;
   9
  10 constexpr bool
  11 test01()
  12 {
  13   int x[] = {1, 2, 3, 4, 5};
  14   auto v = x | views::filter([](int) { return true; });
  15   static_assert( ranges::bidirectional_range<decltype(v)>
  16                  && !ranges::random_access_range<decltype(v)> );
  17   auto f = [](int& x, int&& acc) {
  18     return 2 * acc + x;
  19   };
  20   VERIFY( ranges::fold_right(v, 0, f) == 129 );
  21   VERIFY( ranges::fold_right(v, 1, f) == 161 );
  22   VERIFY( ranges::fold_right(v.begin(), v.begin(), 1, f) == 1 );
  23
  24   VERIFY( ranges::fold_right_last(v, f).value() == 129 );
  25   VERIFY( !ranges::fold_right_last(v.begin(), v.begin(), f).has_value() );
  26
  27   return true;
  28 }
  29
  30 constexpr bool
  31 test02()
  32 {
  33   double x[] = {0.5, 0.25, 0.125, 0.125};
  34   VERIFY( ranges::fold_right(x, 0, std::plus{}) == 1.0 );
  35
  36   return true;
  37 }
  38
  39 int
  40 main()
  41 {
  42   static_assert(test01());
  43   static_assert(test02());
  44 }