#include <iostream>
using namespace std;

struct Vector {
  double x;
  double y;
};

// 重载 + 运算
Vector operator + (Vector a, Vector b) {
  Vector s;
  s.x = a.x + b.x;
  s.y = a.y + b.y;
  return s;
}

// 重载输出 <<
ostream& operator << (ostream& o, Vector a) {
  o << "(" << a.x << ", " << a.y << ")";
  return o;
}

int main() {
  Vector a, b;
  a.x = 1;
  a.y = 2;
  b.x = 10;
  b.y = 11;

  Vector s = a + b;
  cout << s.x << ", " << s.y << endl;
  operator << (cout, s) << endl;
  cout << s << endl << endl;

  return 0;
}