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, class BinaryOperation>
15// OutputIterator
16// inclusive_scan(InputIterator first, InputIterator last,
17// OutputIterator result,
18// BinaryOperation binary_op, T init); // C++17
19
20#include <algorithm>
21#include <array>
22#include <cassert>
23#include <cstddef>
24#include <functional>
25#include <numeric>
26
27#include "test_macros.h"
28#include "test_iterators.h"
29
30template <class Iter1, class T, class Op>
31TEST_CONSTEXPR_CXX20 void
32test(Iter1 first, Iter1 last, Op op, T init, const T *rFirst, const T *rLast)
33{
34 assert((rLast - rFirst) <= 5); // or else increase the size of "out"
35 T out[5];
36
37 // Not in place
38 T *end = std::inclusive_scan(first, last, out, op, init);
39 assert(std::equal(out, end, rFirst, rLast));
40
41 // In place
42 std::copy(first, last, out);
43 end = std::inclusive_scan(out, end, out, op, init);
44 assert(std::equal(out, end, rFirst, rLast));
45}
46
47
48template <class Iter>
49TEST_CONSTEXPR_CXX20 void
50test()
51{
52 int ia[] = {1, 3, 5, 7, 9};
53 const int pRes[] = {1, 4, 9, 16, 25};
54 const int mRes[] = {1, 3, 15, 105, 945};
55 const unsigned sa = sizeof(ia) / sizeof(ia[0]);
56 static_assert(sa == sizeof(pRes) / sizeof(pRes[0])); // just to be sure
57 static_assert(sa == sizeof(mRes) / sizeof(mRes[0])); // just to be sure
58
59 for (unsigned int i = 0; i < sa; ++i ) {
60 test(Iter(ia), Iter(ia + i), std::plus<>(), 0, pRes, pRes + i);
61 test(Iter(ia), Iter(ia + i), std::multiplies<>(), 1, mRes, mRes + i);
62 }
63}
64
65constexpr std::size_t triangle(size_t n) { return n*(n+1)/2; }
66
67// Basic sanity
68TEST_CONSTEXPR_CXX20 void
69basic_tests()
70{
71 {
72 std::array<std::size_t, 10> v;
73 std::fill(first: v.begin(), last: v.end(), value: 3);
74 std::inclusive_scan(first: v.begin(), last: v.end(), result: v.begin(), binary_op: std::plus<>(), init: std::size_t{50});
75 for (std::size_t i = 0; i < v.size(); ++i)
76 assert(v[i] == 50 + (i+1) * 3);
77 }
78
79 {
80 std::array<std::size_t, 10> v;
81 std::iota(first: v.begin(), last: v.end(), value: 0);
82 std::inclusive_scan(first: v.begin(), last: v.end(), result: v.begin(), binary_op: std::plus<>(), init: std::size_t{40});
83 for (std::size_t i = 0; i < v.size(); ++i)
84 assert(v[i] == 40 + triangle(i));
85 }
86
87 {
88 std::array<std::size_t, 10> v;
89 std::iota(first: v.begin(), last: v.end(), value: 1);
90 std::inclusive_scan(first: v.begin(), last: v.end(), result: v.begin(), binary_op: std::plus<>(), init: std::size_t{30});
91 for (std::size_t i = 0; i < v.size(); ++i)
92 assert(v[i] == 30 + triangle(i + 1));
93 }
94
95 {
96 std::array<std::size_t, 0> v, res;
97 std::inclusive_scan(first: v.begin(), last: v.end(), result: res.begin(), binary_op: std::plus<>(), init: std::size_t{40});
98 assert(res.empty());
99 }
100
101// Make sure that the calculations are done using the init typedef
102 {
103 std::array<unsigned char, 10> v;
104 std::iota(first: v.begin(), last: v.end(), value: static_cast<unsigned char>(1));
105 std::array<std::size_t, 10> res;
106 std::inclusive_scan(first: v.begin(), last: v.end(), result: res.begin(), binary_op: std::multiplies<>(), init: std::size_t{1});
107
108 assert(res.size() == 10);
109 std::size_t j = 1;
110 assert(res[0] == 1);
111 for (std::size_t i = 1; i < v.size(); ++i)
112 {
113 j *= i + 1;
114 assert(res[i] == j);
115 }
116 }
117}
118
119TEST_CONSTEXPR_CXX20 bool
120test()
121{
122 basic_tests();
123
124// All the iterator categories
125 test<cpp17_input_iterator <const int*> >();
126 test<forward_iterator <const int*> >();
127 test<bidirectional_iterator<const int*> >();
128 test<random_access_iterator<const int*> >();
129 test<const int*>();
130 test< int*>();
131
132 return true;
133}
134
135int main(int, char**)
136{
137 test();
138#if TEST_STD_VER > 17
139 static_assert(test());
140#endif
141 return 0;
142}
143

source code of libcxx/test/std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op_init.pass.cpp