llvm-project
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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
20template <typename Map>
21struct CallCompMember : Map::value_compare {
22CallCompMember(const typename Map::value_compare& vc) : Map::value_compare(vc) {}
23
24typedef typename Map::value_type value_type;
25bool operator()(const value_type& value1, const value_type& value2) const {
26return this->comp(value1.first, value2.first);
27}
28};
29
30int main(int, char**) {
31typedef std::map<int, std::string> map_type;
32
33map_type m;
34std::pair<map_type::iterator, bool> p1 = m.insert(map_type::value_type(1, "abc"));
35std::pair<map_type::iterator, bool> p2 = m.insert(map_type::value_type(2, "abc"));
36
37const map_type::value_compare vc = m.value_comp();
38CallCompMember<map_type> call_comp = m.value_comp();
39
40assert(vc(*p1.first, *p2.first));
41assert(call_comp(*p1.first, *p2.first));
42
43assert(!vc(*p2.first, *p1.first));
44assert(!call_comp(*p2.first, *p1.first));
45
46return 0;
47}
48