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 // <algorithm>
10
11 // template<RandomAccessIterator Iter>
12 // requires ShuffleIterator<Iter>
13 // void
14 // random_shuffle(Iter first, Iter last);
15
16 // REQUIRES: c++03 || c++11 || c++14
17 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
18
19 #include <algorithm>
20 #include <cassert>
21
22 #include "test_macros.h"
23 #include "test_iterators.h"
24
25 template <class Iter>
26 void
test_with_iterator()27 test_with_iterator()
28 {
29 int empty[] = {};
30 std::random_shuffle(Iter(empty), Iter(empty));
31
32 const int all_elements[] = {1, 2, 3, 4};
33 int shuffled[] = {1, 2, 3, 4};
34 const unsigned size = sizeof(all_elements)/sizeof(all_elements[0]);
35
36 std::random_shuffle(Iter(shuffled), Iter(shuffled+size));
37 assert(std::is_permutation(shuffled, shuffled+size, all_elements));
38
39 std::random_shuffle(Iter(shuffled), Iter(shuffled+size));
40 assert(std::is_permutation(shuffled, shuffled+size, all_elements));
41 }
42
43
main(int,char **)44 int main(int, char**)
45 {
46 int ia[] = {1, 2, 3, 4};
47 int ia1[] = {1, 4, 3, 2};
48 int ia2[] = {4, 1, 2, 3};
49 const unsigned sa = sizeof(ia)/sizeof(ia[0]);
50
51 std::random_shuffle(ia, ia+sa);
52 LIBCPP_ASSERT(std::equal(ia, ia+sa, ia1));
53 assert(std::is_permutation(ia, ia+sa, ia1));
54
55 std::random_shuffle(ia, ia+sa);
56 LIBCPP_ASSERT(std::equal(ia, ia+sa, ia2));
57 assert(std::is_permutation(ia, ia+sa, ia2));
58
59 test_with_iterator<random_access_iterator<int*> >();
60 test_with_iterator<int*>();
61
62 return 0;
63 }
64