1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
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
factorial(int x)25 int factorial(int x)
26 {
27 int r = 1;
28 for (; x; --x)
29 r *= x;
30 return r;
31 }
32
33 template <class Iter>
34 void
test()35 test()
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
main()61 int main()
62 {
63 test<bidirectional_iterator<int*> >();
64 test<random_access_iterator<int*> >();
65 test<int*>();
66 }
67