C++: structured binding declaration

개요

• rvalue의 하위 요소를 바인딩

예제

• 코드

    #include <iostream>
    #include <string>
    #include <tuple>

    using namespace std;

    void test1() {
    	int i[2] = {1, 3};

    	auto [x1, y1] = i;
    	cout << x1 << ", " << y1 << endl;
    	++x1;
    	cout << i[0] << ", " << i[1] << endl;

    	cout << endl;

    	auto &[x2, y2] = i;
    	cout << x1 << ", " << y1 << endl;
    	++x2;
    	cout << i[0] << ", " << i[1] << endl;
    }

    void test2() {
    	tuple<int, string> t = make_tuple(1, "a");

    	cout << get<0>(t) << ", " << get<1>(t) << endl;
    	++get<0>(t);
    	cout << get<0>(t) << ", " << get<1>(t) << endl;

    	cout << endl;

    	auto [i1, s1] = t;
    	cout << i1 << ", " << s1 << endl;
    	++i1;
    	cout << get<0>(t) << ", " << get<1>(t) << endl;

    	cout << endl;

    	auto &[i2, s2] = t;
    	cout << i2 << ", " << s2 << endl;
    	++i2;
    	cout << get<0>(t) << ", " << get<1>(t) << endl;
    }

    void test3() {
    	struct S {
    			int i;
    			string s;
    	};

    	auto [i, s] = S{1, "a"};
    	cout << i << ", " << s << endl;
    }

    int main() {
    	test1();

    	cout << "------" << endl;

    	test2();

    	cout << "------" << endl;

    	test3();

    	return 0;
    }

• 실행 결과

    1, 3
    1, 3

    2, 3
    2, 3
    ------
    1, a
    2, a

    2, a
    2, a

    2, a
    3, a
    ------
    1, a