int val = func(f(1), g(2));

struct point {
  double x, y;
  point(double x_, double y_) : x(x_), y(y_) {}
};

double operator*(const point& p0, const point& p1)
{
  return p0.x*p1.x + p0.y*p1.y;
}

point f(int i) {
  return point(i*i, i);
}

point g(int i) {
  return point(3*i, -i);
}

int main()
{
  double c = f(2) * g(2); // <= breakpoint here
  return 0;
}