private static void Chapter73()
{
// 7.3.1 Inheriting Fields and Properties
HouseCat garfield = new HouseCat("Garfield", 12.0);
garfield.Eat();
Console.WriteLine(garfield.Tired); // prints true
// 7.3.2 Base
HouseCat spike = new HouseCat("Spike");
Console.WriteLine(spike.Weight); // prints 0
spike.Weight = 13;
Console.WriteLine(spike.Weight); // prints 13
// 7.3.3 override
// We've been introduced to the override keyword already in a previous lecture when
// we were overriding the ToString, Equals and GetHashCode methods that are all
// present in the base Object class.
// When we want to modify the behavior of a method in the base class, we can override it in sub-classes
// In order to accomplish this in our Cat/HouseCat example we will require another new keyword, virtual
Cat plainCat = new Cat(8.6);
HouseCat cheshireCat = new HouseCat("Cheshire Cat", 26.0);
Console.WriteLine(plainCat.Noise()); // prints "Meow!"
Console.WriteLine(cheshireCat.Noise()); // prints "Hello, my name is Cheshire Cat!"
}
private static void Chapter75()
{
// 7.5 Casting
// We've seen casting before when writing our Equals methods in a previous lecture.
// Casting allows us to exploit one of the pillars of OOP, more specifically polymorphism.
// Note: We are declaring suki as a Cat and instantiating as a HouseCat
Cat suki = new HouseCat("Suki", 8);
suki.Noise(); // Meow!
// Results in a compiler error, since Cat doesn't have such a method
// suki.IsSatisfied();
// How do we avoid this? Declare suki as a HouseCat... OR... cast suki to a HouseCat
// As long as suki really is a HouseCat, this works
(suki as HouseCat).IsSatisfied();
// Side note: We can check beforehand to make sure that suki really is of class HouseCat
// before casting, this will prevent a runtime exception being thrown
if (suki is HouseCat)
{
// Since this is true, we can safely cast suki to a HouseCat
(suki as HouseCat).IsSatisfied();
}
}
