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 // UNSUPPORTED: c++03, c++11, c++14
10
11 // <numeric>
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
test(Iter first,Iter last,T x)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
test()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
test_return_type()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
test()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
main(int,char **)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