91 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++1410 11// <numeric>12 13// Became constexpr in C++2014// template<class InputIterator, class T, class BinaryOperation>15// T reduce(InputIterator first, InputIterator last, T init, BinaryOperation op);16 17#include <numeric>18#include <cassert>19#include <functional>20 21#include "test_macros.h"22#include "test_iterators.h"23 24template <class Iter, class T, class Op>25TEST_CONSTEXPR_CXX20 void26test(Iter first, Iter last, T init, Op op, T x)27{28 static_assert( std::is_same_v<T, decltype(std::reduce(first, last, init, op))>, "" );29 assert(std::reduce(first, last, init, op) == x);30}31 32template <class Iter>33TEST_CONSTEXPR_CXX20 void34test()35{36 int ia[] = {1, 2, 3, 4, 5, 6};37 unsigned sa = sizeof(ia) / sizeof(ia[0]);38 test(Iter(ia), Iter(ia), 0, std::plus<>(), 0);39 test(Iter(ia), Iter(ia), 1, std::multiplies<>(), 1);40 test(Iter(ia), Iter(ia+1), 0, std::plus<>(), 1);41 test(Iter(ia), Iter(ia+1), 2, std::multiplies<>(), 2);42 test(Iter(ia), Iter(ia+2), 0, std::plus<>(), 3);43 test(Iter(ia), Iter(ia+2), 3, std::multiplies<>(), 6);44 test(Iter(ia), Iter(ia+sa), 0, std::plus<>(), 21);45 test(Iter(ia), Iter(ia+sa), 4, std::multiplies<>(), 2880);46}47 48template <typename T, typename Init>49TEST_CONSTEXPR_CXX20 void50test_return_type()51{52 T *p = nullptr;53 static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}, std::plus<>()))>, "" );54}55 56TEST_CONSTEXPR_CXX20 bool57test()58{59 test_return_type<char, int>();60 test_return_type<int, int>();61 test_return_type<int, unsigned long>();62 test_return_type<float, int>();63 test_return_type<short, float>();64 test_return_type<double, char>();65 test_return_type<char, double>();66 67 test<cpp17_input_iterator<const int*> >();68 test<forward_iterator<const int*> >();69 test<bidirectional_iterator<const int*> >();70 test<random_access_iterator<const int*> >();71 test<const int*>();72 73// Make sure the math is done using the correct type74 {75 auto v = {1, 2, 3, 4, 5, 6, 7, 8};76 unsigned res = std::reduce(v.begin(), v.end(), 1U, std::multiplies<>());77 assert(res == 40320); // 8! will not fit into a char78 }79 80 return true;81}82 83int main(int, char**)84{85 test();86#if TEST_STD_VER > 1787 static_assert(test());88#endif89 return 0;90}91