#include <iostream>
#include <string>
#include <functional>

	struct A {
		const std::string& s;
		A(const std::string& s) : s(s) {}
	//	A(std::reference_wrapper<const std::string> r) : s(r.get()) {}
	};
	
	int main() {
		A a("abc");
		std::cout << a.s << std::endl;
		return 0;
	}