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, class OutputIterator, class T>
15// OutputIterator exclusive_scan(InputIterator first, InputIterator last,
16// OutputIterator result, T init);
17//
18
19#include <algorithm>
20#include <array>
21#include <cassert>
22#include <cstddef>
23#include <numeric>
24
25#include "test_macros.h"
26#include "test_iterators.h"
27
28template <class Iter1, class T>
29TEST_CONSTEXPR_CXX20 void
30test(Iter1 first, Iter1 last, T init, const T *rFirst, const T *rLast)
31{
32 assert((rLast - rFirst) <= 5); // or else increase the size of "out"
33 T out[5];
34
35 // Not in place
36 T *end = std::exclusive_scan(first, last, out, init);
37 assert(std::equal(out, end, rFirst, rLast));
38
39 // In place
40 std::copy(first, last, out);
41 end = std::exclusive_scan(out, end, out, init);
42 assert(std::equal(out, end, rFirst, rLast));
43}
44
45template <class Iter>
46TEST_CONSTEXPR_CXX20 void
47test()
48{
49 int ia[] = {1, 3, 5, 7, 9};
50 const int pRes[] = {0, 1, 4, 9, 16};
51 const unsigned sa = sizeof(ia) / sizeof(ia[0]);
52 static_assert(sa == sizeof(pRes) / sizeof(pRes[0])); // just to be sure
53
54 for (unsigned int i = 0; i < sa; ++i) {
55 test(Iter(ia), Iter(ia + i), 0, pRes, pRes + i);
56 }
57}
58
59constexpr std::size_t triangle(size_t n) { return n*(n+1)/2; }
60
61// Basic sanity
62TEST_CONSTEXPR_CXX20 void
63basic_tests()
64{
65 {
66 std::array<std::size_t, 10> v;
67 std::fill(first: v.begin(), last: v.end(), value: 3);
68 std::exclusive_scan(first: v.begin(), last: v.end(), result: v.begin(), init: std::size_t{50});
69 for (std::size_t i = 0; i < v.size(); ++i)
70 assert(v[i] == 50 + i * 3);
71 }
72
73 {
74 std::array<std::size_t, 10> v;
75 std::iota(first: v.begin(), last: v.end(), value: 0);
76 std::exclusive_scan(first: v.begin(), last: v.end(), result: v.begin(), init: std::size_t{30});
77 for (std::size_t i = 0; i < v.size(); ++i)
78 assert(v[i] == 30 + triangle(i-1));
79 }
80
81 {
82 std::array<std::size_t, 10> v;
83 std::iota(first: v.begin(), last: v.end(), value: 1);
84 std::exclusive_scan(first: v.begin(), last: v.end(), result: v.begin(), init: std::size_t{40});
85 for (std::size_t i = 0; i < v.size(); ++i)
86 assert(v[i] == 40 + triangle(i));
87 }
88
89}
90
91TEST_CONSTEXPR_CXX20 bool
92test()
93{
94 basic_tests();
95
96// All the iterator categories
97 test<cpp17_input_iterator <const int*> >();
98 test<forward_iterator <const int*> >();
99 test<bidirectional_iterator<const int*> >();
100 test<random_access_iterator<const int*> >();
101 test<const int*>();
102 test< int*>();
103
104 return true;
105}
106
107int main(int, char**)
108{
109 test();
110#if TEST_STD_VER > 17
111 static_assert(test());
112#endif
113 return 0;
114}
115

source code of libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp