```/* <![CDATA[ */
function get_sym_list(){return [["Function","xf",[["factorial",25],["main",61],["test",35]]]];} /* ]]> */1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
7//
8//===----------------------------------------------------------------------===//
9
10// <algorithm>
11
12// template<BidirectionalIterator Iter>
13//   requires ShuffleIterator<Iter>
14//         && LessThanComparable<Iter::value_type>
15//   bool
16//   next_permutation(Iter first, Iter last);
17
18#include <algorithm>
19#include <cassert>
20
21#include "test_iterators.h"
22
23#include <cstdio>
24
25int factorial(int x)
26{
27    int r = 1;
28    for (; x; --x)
29        r *= x;
30    return r;
31}
32
33template <class Iter>
34void
35test()
36{
37    int ia[] = {1, 2, 3, 4, 5, 6};
38    const int sa = sizeof(ia)/sizeof(ia[0]);
39    int prev[sa];
40    for (int e = 0; e <= sa; ++e)
41    {
42        int count = 0;
43        bool x;
44        do
45        {
46            std::copy(ia, ia+e, prev);
47            x = std::next_permutation(Iter(ia), Iter(ia+e));
48            if (e > 1)
49            {
50                if (x)
51                    assert(std::lexicographical_compare(prev, prev+e, ia, ia+e));
52                else
53                    assert(std::lexicographical_compare(ia, ia+e, prev, prev+e));
54            }
55            ++count;
56        } while (x);
57        assert(count == factorial(e));
58    }
59}
60
61int main()
62{
63    test<bidirectional_iterator<int*> >();
64    test<random_access_iterator<int*> >();
65    test<int*>();
66}
67```