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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // <numeric> 10 // UNSUPPORTED: c++03, c++11, c++14 11 // UNSUPPORTED: clang-8 12 // UNSUPPORTED: gcc-9 13 14 // Became constexpr in C++20 15 // template<class InputIterator, class T, class BinaryOperation> 16 // T reduce(InputIterator first, InputIterator last, T init, BinaryOperation op); 17 18 #include <numeric> 19 #include <cassert> 20 21 #include "test_macros.h" 22 #include "test_iterators.h" 23 24 template <class Iter, class T, class Op> 25 TEST_CONSTEXPR_CXX20 void 26 test(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 32 template <class Iter> 33 TEST_CONSTEXPR_CXX20 void 34 test() 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 48 template <typename T, typename Init> 49 TEST_CONSTEXPR_CXX20 void 50 test_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 56 TEST_CONSTEXPR_CXX20 bool 57 test() 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<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 type 74 { 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 char 78 } 79 80 return true; 81 } 82 83 int main(int, char**) 84 { 85 test(); 86 #if TEST_STD_VER > 17 87 static_assert(test()); 88 #endif 89 return 0; 90 } 91