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 // <map>
10
11 // class value_compare
12
13 // bool operator()( const value_type& lhs, const value_type& rhs ) const;
14
15 #include <map>
16 #include <cassert>
17 #include <string>
18 #include <utility>
19
20 template <typename Map>
21 struct CallCompMember : Map::value_compare {
CallCompMemberCallCompMember22 CallCompMember(const typename Map::value_compare& vc) : Map::value_compare(vc) {}
23
24 typedef typename Map::value_type value_type;
operator ()CallCompMember25 bool operator()(const value_type& value1, const value_type& value2) const {
26 return this->comp(value1.first, value2.first);
27 }
28 };
29
main(int,char **)30 int main(int, char**) {
31 typedef std::map<int, std::string> map_type;
32
33 map_type m;
34 std::pair<map_type::iterator, bool> p1 = m.insert(map_type::value_type(1, "abc"));
35 std::pair<map_type::iterator, bool> p2 = m.insert(map_type::value_type(2, "abc"));
36
37 const map_type::value_compare vc = m.value_comp();
38 CallCompMember<map_type> call_comp = m.value_comp();
39
40 assert(vc(*p1.first, *p2.first));
41 assert(call_comp(*p1.first, *p2.first));
42
43 assert(!vc(*p2.first, *p1.first));
44 assert(!call_comp(*p2.first, *p1.first));
45
46 return 0;
47 }
48