[C++] owner_less

개요

• 값 기반이 아닌 소유자 기반 비교

예제

• 코드

   #include <iostream>
   #include <memory>
   #include <set>
      
   using namespace std;
      
   int main() {
   	shared_ptr<int> p1(new int(10));
   	shared_ptr<int> p2(p1, new int(20));
      
   	set<shared_ptr<int>> valueBased;
   	valueBased.insert(p1);
   	valueBased.insert(p2);
   	cout << valueBased.size() << endl;
   	for (const auto &iter : valueBased) {
   		cout << *iter << endl;
   	}
      
   	cout << "------" << endl;
      
   	set<shared_ptr<int>, owner_less<shared_ptr<int>>> ownerBased;
   	ownerBased.insert(p1);
   	ownerBased.insert(p2);
   	cout << ownerBased.size() << endl;
   	for (const auto &iter : ownerBased) {
   		cout << *iter << endl;
   	}
      
   	return 0;
   }
  

• 실행 결과

   2
   10
   20
   ------
   1
   10