xref: /llvm-project/libcxx/test/std/algorithms/alg.sorting/alg.min.max/min_element.pass.cpp (revision 7fc6a55688c816f5fc1a5481ae7af25be7500356)
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<ForwardIterator Iter>
12 //   requires LessThanComparable<Iter::value_type>
13 //   Iter
14 //   min_element(Iter first, Iter last);
15 
16 #include <algorithm>
17 #include <random>
18 #include <cassert>
19 
20 #include "test_macros.h"
21 #include "test_iterators.h"
22 
23 std::mt19937 randomness;
24 
25 template <class Iter>
26 void
test(Iter first,Iter last)27 test(Iter first, Iter last)
28 {
29     Iter i = std::min_element(first, last);
30     if (first != last)
31     {
32         for (Iter j = first; j != last; ++j)
33             assert(!(*j < *i));
34     }
35     else
36         assert(i == last);
37 }
38 
39 template <class Iter>
40 void
test(int N)41 test(int N)
42 {
43     int* a = new int[N];
44     for (int i = 0; i < N; ++i)
45         a[i] = i;
46     std::shuffle(a, a+N, randomness);
47     test(Iter(a), Iter(a+N));
48     delete [] a;
49 }
50 
51 template <class Iter>
52 void
test()53 test()
54 {
55     test<Iter>(0);
56     test<Iter>(1);
57     test<Iter>(2);
58     test<Iter>(3);
59     test<Iter>(10);
60     test<Iter>(1000);
61 }
62 
63 #if TEST_STD_VER >= 14
64 constexpr int il[] = { 2, 4, 6, 8, 7, 5, 3, 1 };
65 #endif
66 
constexpr_test()67 void constexpr_test()
68 {
69 #if TEST_STD_VER >= 14
70     constexpr auto p = std::min_element(il, il+8);
71     static_assert ( *p == 1, "" );
72 #endif
73 }
74 
main(int,char **)75 int main(int, char**)
76 {
77     test<forward_iterator<const int*> >();
78     test<bidirectional_iterator<const int*> >();
79     test<random_access_iterator<const int*> >();
80     test<const int*>();
81 
82     constexpr_test();
83 
84   return 0;
85 }
86