libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <algorithm>

// template<class RandomAccessIterator, class UniformRandomNumberGenerator>
//     void shuffle(RandomAccessIterator first, RandomAccessIterator last,
//                  UniformRandomNumberGenerator& g);

#include <algorithm>
#include <random>
#include <cassert>

#include "test_macros.h"

int main(int, char**)
{
    int ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int ia1[] = {2, 7, 1, 4, 3, 6, 5, 10, 9, 8};
    int ia2[] = {1, 8, 3, 4, 6, 9, 5, 7, 2, 10};
    const unsigned sa = sizeof(ia)/sizeof(ia[0]);
    std::minstd_rand g;
    std::shuffle(ia, ia+sa, g);
    LIBCPP_ASSERT(std::equal(ia, ia+sa, ia1));
    assert(std::is_permutation(ia, ia+sa, ia1));
    std::shuffle(ia, ia+sa, std::move(g));
    LIBCPP_ASSERT(std::equal(ia, ia+sa, ia2));
    assert(std::is_permutation(ia, ia+sa, ia2));

  return 0;
}