83 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>15// T reduce(InputIterator first, InputIterator last, T init);16 17#include <numeric>18#include <cassert>19 20#include "test_macros.h"21#include "test_iterators.h"22 23template <class Iter, class T>24TEST_CONSTEXPR_CXX20 void25test(Iter first, Iter last, T init, T x)26{27 static_assert( std::is_same_v<T, decltype(std::reduce(first, last, init))> );28 assert(std::reduce(first, last, init) == x);29}30 31template <class Iter>32TEST_CONSTEXPR_CXX20 void33test()34{35 int ia[] = {1, 2, 3, 4, 5, 6};36 unsigned sa = sizeof(ia) / sizeof(ia[0]);37 test(Iter(ia), Iter(ia), 0, 0);38 test(Iter(ia), Iter(ia), 1, 1);39 test(Iter(ia), Iter(ia+1), 0, 1);40 test(Iter(ia), Iter(ia+1), 2, 3);41 test(Iter(ia), Iter(ia+2), 0, 3);42 test(Iter(ia), Iter(ia+2), 3, 6);43 test(Iter(ia), Iter(ia+sa), 0, 21);44 test(Iter(ia), Iter(ia+sa), 4, 25);45}46 47template <typename T, typename Init>48TEST_CONSTEXPR_CXX20 void49test_return_type()50{51 T *p = nullptr;52 static_assert( std::is_same_v<Init, decltype(std::reduce(p, p, Init{}))> );53}54 55TEST_CONSTEXPR_CXX20 bool56test()57{58 test_return_type<char, int>();59 test_return_type<int, int>();60 test_return_type<int, unsigned long>();61 test_return_type<float, int>();62 test_return_type<short, float>();63 test_return_type<double, char>();64 test_return_type<char, double>();65 66 test<cpp17_input_iterator<const int*> >();67 test<forward_iterator<const int*> >();68 test<bidirectional_iterator<const int*> >();69 test<random_access_iterator<const int*> >();70 test<const int*>();71 72 return true;73}74 75int main(int, char**)76{77 test();78#if TEST_STD_VER > 1779 static_assert(test());80#endif81 return 0;82}83