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, Callable<auto, Iter::difference_type> Rand>
12// requires ShuffleIterator<Iter>
13// && Convertible<Rand::result_type, Iter::difference_type>
14// void
15// random_shuffle(Iter first, Iter last, Rand&& rand);
16
17// REQUIRES: c++03 || c++11 || c++14
18// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
19
20#include <algorithm>
21#include <cassert>
22#include <cstddef>
23
24#include "test_macros.h"
25#include "test_iterators.h"
26
27
28struct gen
29{
30 std::ptrdiff_t operator()(std::ptrdiff_t n)
31 {
32 return n-1;
33 }
34};
35
36
37template <class Iter>
38void
39test_with_iterator()
40{
41
42 int ia[] = {1, 2, 3, 4};
43 int ia1[] = {4, 1, 2, 3};
44 const unsigned sa = sizeof(ia)/sizeof(ia[0]);
45 gen r;
46
47 std::random_shuffle(first: ia, last: ia+sa, rand&: r);
48 LIBCPP_ASSERT(std::equal(first1: ia, last1: ia+sa, first2: ia1));
49 assert(std::is_permutation(ia, ia+sa, ia1));
50
51 std::random_shuffle(first: ia, last: ia+sa, rand&: r);
52 assert(std::is_permutation(ia, ia+sa, ia1));
53}
54
55
56int main(int, char**)
57{
58 test_with_iterator<random_access_iterator<int*> >();
59 test_with_iterator<int*>();
60 return 0;
61}
62

source code of libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_rand.pass.cpp