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 13 // Became constexpr in C++20 14 // template<class InputIterator> 15 // typename iterator_traits<InputIterator>::value_type 16 // reduce(InputIterator first, InputIterator last); 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> 25 TEST_CONSTEXPR_CXX20 void 26 test(Iter first, Iter last, T x) 27 { 28 static_assert( std::is_same_v<typename std::iterator_traits<decltype(first)>::value_type, 29 decltype(std::reduce(first, last))> ); 30 assert(std::reduce(first, last) == x); 31 } 32 33 template <class Iter> 34 TEST_CONSTEXPR_CXX20 void 35 test() 36 { 37 int ia[] = {1, 2, 3, 4, 5, 6}; 38 unsigned sa = sizeof(ia) / sizeof(ia[0]); 39 test(Iter(ia), Iter(ia), 0); 40 test(Iter(ia), Iter(ia+1), 1); 41 test(Iter(ia), Iter(ia+2), 3); 42 test(Iter(ia), Iter(ia+sa), 21); 43 } 44 45 template <typename T> 46 TEST_CONSTEXPR_CXX20 void 47 test_return_type() 48 { 49 T *p = nullptr; 50 static_assert( std::is_same_v<T, decltype(std::reduce(p, p))> ); 51 } 52 53 TEST_CONSTEXPR_CXX20 bool 54 test() 55 { 56 test_return_type<char>(); 57 test_return_type<int>(); 58 test_return_type<unsigned long>(); 59 test_return_type<float>(); 60 test_return_type<double>(); 61 62 test<cpp17_input_iterator<const int*> >(); 63 test<forward_iterator<const int*> >(); 64 test<bidirectional_iterator<const int*> >(); 65 test<random_access_iterator<const int*> >(); 66 test<const int*>(); 67 68 return true; 69 } 70 71 int main(int, char**) 72 { 73 test(); 74 #if TEST_STD_VER > 17 75 static_assert(test()); 76 #endif 77 return 0; 78 } 79