public vector reverse_vector(vector v)
{
vector u = new vector(-v.a, -v.b);
return(u);
}
public directional_vector(vector vector, double direction)
{
this.vector = vector;
this.direction = direction;
}
public vector flip_vector(vector u)
{
vector v = new vector(u.a, -u.b);
return(v);
}