Virtual Properties

Like method, properties can also be virtualized. Let's create another class called FastInvader. Don't forget to create a constructor and inherit it from Invader class.

class FastInvader : Invader
{
    public FastInvader(Path path) : base(path)
    { }
}

The behavior of FastInvader is it will move further than normal Invader. We could do the same like DecreasedHealth method earlier. Unfortunately, we will learn something new now.

// in Invader class
protected virtual int stepSize { get; } = 1;

Copy it to FastInvader class.

protected override int stepSize { get; } = 2;

That is the power of encaspsulation, inheritance and polymorphism principles in OOP. We can create another modified object with different attributes and behaviors from its origin object.