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<InputIterator Iter, Predicate<auto, Iter::value_type> Pred>
13 // requires CopyConstructible<Pred>
14 // constexpr Iter::difference_type // constexpr after C++17
15 // count_if(Iter first, Iter last, Pred pred);
16
17 #include <algorithm>
18 #include <functional>
19 #include <cassert>
20
21 #include "test_macros.h"
22 #include "test_iterators.h"
23
24 struct eq {
eqeq25 TEST_CONSTEXPR eq (int val) : v(val) {}
operator ()eq26 TEST_CONSTEXPR bool operator () (int v2) const { return v == v2; }
27 int v;
28 };
29
30 #if TEST_STD_VER > 17
test_constexpr()31 TEST_CONSTEXPR bool test_constexpr() {
32 int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
33 int ib[] = {1, 2, 3, 4, 5, 6};
34 return (std::count_if(std::begin(ia), std::end(ia), eq(2)) == 3)
35 && (std::count_if(std::begin(ib), std::end(ib), eq(9)) == 0)
36 ;
37 }
38 #endif
39
main()40 int main()
41 {
42 int ia[] = {0, 1, 2, 2, 0, 1, 2, 3};
43 const unsigned sa = sizeof(ia)/sizeof(ia[0]);
44 assert(std::count_if(input_iterator<const int*>(ia),
45 input_iterator<const int*>(ia + sa),
46 eq(2)) == 3);
47 assert(std::count_if(input_iterator<const int*>(ia),
48 input_iterator<const int*>(ia + sa),
49 eq(7)) == 0);
50 assert(std::count_if(input_iterator<const int*>(ia),
51 input_iterator<const int*>(ia),
52 eq(2)) == 0);
53
54 #if TEST_STD_VER > 17
55 static_assert(test_constexpr());
56 #endif
57 }
58