default_copy_constructor_on_vec.cpp

#include <iostream>
#include <vector>

using namespace std;

struct S {
	vector<int> a;	
	S() { a.clear(); }
	S(const S& toher) = default;
};

int main() {
	S b;
	b.a.clear();
	b.a.push_back(3);
	S c = b;
	cout << c.a.size() << endl;
	cout << b.a[0] << " " << c.a[0] << endl;
	b.a[0] = 2;
	cout << b.a[0] << " " << c.a[0] << endl;
	c.a[0] = 5;
	cout << b.a[0] << " " << c.a[0] << endl;
	return 0;
}