| //===----------------------------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // <algorithm> |
| // UNSUPPORTED: c++98, c++03, c++11, c++14 |
| |
| // template<class InputIterator, class Size, class Function> |
| // constexpr InputIterator // constexpr after C++17 |
| // for_each_n(InputIterator first, Size n, Function f); |
| |
| |
| #include <algorithm> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| #include "test_iterators.h" |
| |
| #if TEST_STD_VER > 17 |
| TEST_CONSTEXPR bool test_constexpr() { |
| int ia[] = {1, 3, 6, 7}; |
| int expected[] = {3, 5, 8, 9}; |
| const size_t N = 4; |
| |
| auto it = std::for_each_n(std::begin(ia), N, [](int &a) { a += 2; }); |
| return it == (std::begin(ia) + N) |
| && std::equal(std::begin(ia), std::end(ia), std::begin(expected)) |
| ; |
| } |
| #endif |
| |
| struct for_each_test |
| { |
| for_each_test(int c) : count(c) {} |
| int count; |
| void operator()(int& i) {++i; ++count;} |
| }; |
| |
| int main() |
| { |
| typedef input_iterator<int*> Iter; |
| int ia[] = {0, 1, 2, 3, 4, 5}; |
| const unsigned s = sizeof(ia)/sizeof(ia[0]); |
| |
| { |
| auto f = for_each_test(0); |
| Iter it = std::for_each_n(Iter(ia), 0, std::ref(f)); |
| assert(it == Iter(ia)); |
| assert(f.count == 0); |
| } |
| |
| { |
| auto f = for_each_test(0); |
| Iter it = std::for_each_n(Iter(ia), s, std::ref(f)); |
| |
| assert(it == Iter(ia+s)); |
| assert(f.count == s); |
| for (unsigned i = 0; i < s; ++i) |
| assert(ia[i] == static_cast<int>(i+1)); |
| } |
| |
| { |
| auto f = for_each_test(0); |
| Iter it = std::for_each_n(Iter(ia), 1, std::ref(f)); |
| |
| assert(it == Iter(ia+1)); |
| assert(f.count == 1); |
| for (unsigned i = 0; i < 1; ++i) |
| assert(ia[i] == static_cast<int>(i+2)); |
| } |
| |
| #if TEST_STD_VER > 17 |
| static_assert(test_constexpr()); |
| #endif |
| } |