Lesson29

#include <iostream>

using namespace std;

struct Point { double x; double y; };
struct Vector { double x; double y; };
Point operator+(const Point& p, const Vector& v) { return {p.x + v.x, p.y + v.y}; }
Vector operator+(const Vector& v1, const Vector& v2) { return {v1.x + v2.x, v1.y + v2.y}; }
Vector operator-(const Vector& v1, const Vector& v2) { return {v1.x - v2.x, v1.y - v2.y}; }
double DotProduct(const Vector& v1, const Vector& v2) { return v1.x * v2.x + v1.y * v2.y; }
double CrossProduct(const Vector& v1, const Vector& v2) { return v1.x * v2.y - v1.y * v2.x; }
istream& operator>>(istream& in, Point& p) { return in >> p.x >> p.y; }
ostream& operator<<(ostream& out, const Point& p) { return out << p.x << " " << p.y; }
istream& operator>>(istream& in, Vector& v) { return in >> v.x >> v.y; }
ostream& operator<<(ostream& out, const Vector& v) { return out << v.x << " " << v.y; }

int main() {
//  Point p; Vector v;
//  cin >> p >> v;
//  cout << p + v;
  Vector v1, v2; cin >> v1 >> v2;
  cout << DotProduct(v1, v2) << "\n";
  cout << CrossProduct(v1, v2) << "\n";
  return 0;
}