| // { dg-options "-std=gnu++23" } |
| // { dg-do run { target c++23 } } |
| |
| #include <algorithm> |
| #include <ranges> |
| #include <testsuite_iterators.h> |
| |
| #if __cpp_lib_ranges_fold != 202207L |
| # error "Feature-test macro __cpp_lib_ranges_fold has wrong value in <algorithm>" |
| #endif |
| |
| namespace ranges = std::ranges; |
| namespace views = std::views; |
| |
| constexpr bool |
| test01() |
| { |
| int x[] = {1, 2, 3, 4, 5}; |
| auto f = [](int&& acc, int& x) { |
| return 2 * acc + x; |
| }; |
| VERIFY( ranges::fold_left(x, 0, f) == 57 ); |
| VERIFY( ranges::fold_left(x, 1, f) == 89 ); |
| VERIFY( ranges::fold_left(x+0, x+0, 1, f) == 1 ); |
| |
| VERIFY( ranges::fold_left_first(x, f).value() == 57 ); |
| VERIFY( !ranges::fold_left_first(x+0, x+0, f).has_value() ); |
| |
| return true; |
| } |
| |
| void |
| test02() |
| { |
| int x[] = {1, 2, 3, 4, 5}; |
| auto f = [](int&& acc, int& x) { |
| return 2 * acc + x; |
| }; |
| |
| __gnu_test::test_input_range<int> rx(x); |
| ranges::in_value_result ivr = ranges::fold_left_with_iter(rx, 0, f); |
| VERIFY( ivr.in == rx.end() ); |
| VERIFY( ivr.value == 57 ); |
| |
| rx.bounds.first = x; |
| ranges::in_value_result ivr2 = ranges::fold_left_first_with_iter(rx, f); |
| VERIFY( ivr2.in == rx.end() ); |
| VERIFY( ivr2.value.value() == 57 ); |
| |
| rx.bounds.first = x; |
| auto v = rx | views::take(0); |
| ranges::in_value_result ivr3 = ranges::fold_left_first_with_iter(v, f); |
| VERIFY( ivr3.in == v.end() ); |
| VERIFY( !ivr3.value.has_value() ); |
| } |
| |
| constexpr bool |
| test03() |
| { |
| double x[] = {0.5, 0.25, 0.125, 0.125}; |
| VERIFY( ranges::fold_left(x, 0, std::plus{}) == 1.0 ); |
| VERIFY( ranges::fold_left_with_iter(x, 0, std::plus{}).value == 1.0 ); |
| |
| return true; |
| } |
| |
| int |
| main() |
| { |
| static_assert(test01()); |
| test02(); |
| static_assert(test03()); |
| } |