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
11// Became constexpr in C++20
12// template <InputIterator Iter, MoveConstructible T,
13// Callable<auto, const T&, Iter::reference> BinaryOperation>
14// requires HasAssign<T, BinaryOperation::result_type>
15// && CopyConstructible<BinaryOperation>
16// T
17// accumulate(Iter first, Iter last, T init, BinaryOperation binary_op);
18
19#include <numeric>
20#include <functional>
21#include <string>
22#include <cassert>
23
24#include "test_macros.h"
25#include "test_iterators.h"
26
27#if TEST_STD_VER > 17
28struct rvalue_addable
29{
30 bool correctOperatorUsed = false;
31
32 // make sure the predicate is passed an rvalue and an lvalue (so check that the first argument was moved)
33 constexpr rvalue_addable operator()(rvalue_addable&& r, rvalue_addable const&) {
34 r.correctOperatorUsed = true;
35 return std::move(r);
36 }
37};
38
39constexpr rvalue_addable operator+(rvalue_addable& lhs, rvalue_addable const&)
40{
41 lhs.correctOperatorUsed = false;
42 return lhs;
43}
44
45constexpr rvalue_addable operator+(rvalue_addable&& lhs, rvalue_addable const&)
46{
47 lhs.correctOperatorUsed = true;
48 return std::move(lhs);
49}
50
51constexpr void
52test_use_move()
53{
54 rvalue_addable arr[100];
55 auto res1 = std::accumulate(arr, arr + 100, rvalue_addable());
56 auto res2 = std::accumulate(arr, arr + 100, rvalue_addable(), /*predicate=*/rvalue_addable());
57 assert(res1.correctOperatorUsed);
58 assert(res2.correctOperatorUsed);
59}
60#endif // TEST_STD_VER > 17
61
62TEST_CONSTEXPR_CXX20 void test_string() {
63 std::string sa[] = {"a", "b", "c"};
64 assert(std::accumulate(sa, sa + 3, std::string()) == "abc");
65 assert(std::accumulate(sa, sa + 3, std::string(), std::plus<std::string>()) == "abc");
66}
67
68template <class Iter, class T>
69TEST_CONSTEXPR_CXX20 void
70test(Iter first, Iter last, T init, T x)
71{
72 assert(std::accumulate(first, last, init, std::multiplies<T>()) == x);
73}
74
75template <class Iter>
76TEST_CONSTEXPR_CXX20 void
77test()
78{
79 int ia[] = {1, 2, 3, 4, 5, 6};
80 unsigned sa = sizeof(ia) / sizeof(ia[0]);
81 test(Iter(ia), Iter(ia), 1, 1);
82 test(Iter(ia), Iter(ia), 10, 10);
83 test(Iter(ia), Iter(ia+1), 1, 1);
84 test(Iter(ia), Iter(ia+1), 10, 10);
85 test(Iter(ia), Iter(ia+2), 1, 2);
86 test(Iter(ia), Iter(ia+2), 10, 20);
87 test(Iter(ia), Iter(ia+sa), 1, 720);
88 test(Iter(ia), Iter(ia+sa), 10, 7200);
89}
90
91TEST_CONSTEXPR_CXX20 bool
92test()
93{
94 test<cpp17_input_iterator<const int*> >();
95 test<forward_iterator<const int*> >();
96 test<bidirectional_iterator<const int*> >();
97 test<random_access_iterator<const int*> >();
98 test<const int*>();
99
100#if TEST_STD_VER > 17
101 test_use_move();
102#endif // TEST_STD_VER > 17
103
104 test_string();
105
106 return true;
107}
108
109int main(int, char**)
110{
111 test();
112#if TEST_STD_VER > 17
113 static_assert(test());
114#endif
115 return 0;
116}
117

source code of libcxx/test/std/numerics/numeric.ops/accumulate/accumulate_op.pass.cpp