libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/test.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <algorithm>

// template<InputIterator Iter, Callable<auto, Iter::reference> Function>
//   requires CopyConstructible<Function>
//   constexpr Function   // constexpr after C++17
//   for_each(Iter first, Iter last, 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};

    std::for_each(std::begin(ia), std::end(ia), [](int &a) { a += 2; });
    return 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(int, char**)
{
    int ia[] = {0, 1, 2, 3, 4, 5};
    const unsigned s = sizeof(ia)/sizeof(ia[0]);
    for_each_test f = std::for_each(input_iterator<int*>(ia),
                                    input_iterator<int*>(ia+s),
                                    for_each_test(0));
    assert(f.count == s);
    for (unsigned i = 0; i < s; ++i)
        assert(ia[i] == static_cast<int>(i+1));

#if TEST_STD_VER > 17
    static_assert(test_constexpr());
#endif

  return 0;
}