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> 16 // typename iterator_traits<InputIterator>::value_type 17 // reduce(InputIterator first, InputIterator last); 18 19 #include <numeric> 20 #include <cassert> 21 22 #include "test_macros.h" 23 #include "test_iterators.h" 24 25 template <class Iter, class T> 26 TEST_CONSTEXPR_CXX20 void 27 test(Iter first, Iter last, T x) 28 { 29 static_assert( std::is_same_v<typename std::iterator_traits<decltype(first)>::value_type, 30 decltype(std::reduce(first, last))> ); 31 assert(std::reduce(first, last) == x); 32 } 33 34 template <class Iter> 35 TEST_CONSTEXPR_CXX20 void 36 test() 37 { 38 int ia[] = {1, 2, 3, 4, 5, 6}; 39 unsigned sa = sizeof(ia) / sizeof(ia[0]); 40 test(Iter(ia), Iter(ia), 0); 41 test(Iter(ia), Iter(ia+1), 1); 42 test(Iter(ia), Iter(ia+2), 3); 43 test(Iter(ia), Iter(ia+sa), 21); 44 } 45 46 template <typename T> 47 TEST_CONSTEXPR_CXX20 void 48 test_return_type() 49 { 50 T *p = nullptr; 51 static_assert( std::is_same_v<T, decltype(std::reduce(p, p))> ); 52 } 53 54 TEST_CONSTEXPR_CXX20 bool 55 test() 56 { 57 test_return_type<char>(); 58 test_return_type<int>(); 59 test_return_type<unsigned long>(); 60 test_return_type<float>(); 61 test_return_type<double>(); 62 63 test<cpp17_input_iterator<const int*> >(); 64 test<forward_iterator<const int*> >(); 65 test<bidirectional_iterator<const int*> >(); 66 test<random_access_iterator<const int*> >(); 67 test<const int*>(); 68 69 return true; 70 } 71 72 int main(int, char**) 73 { 74 test(); 75 #if TEST_STD_VER > 17 76 static_assert(test()); 77 #endif 78 return 0; 79 } 80