Classes

Question 1

attr_acessor

Answer 1

• allows you to access variables inside and outside the class
• ruby is actually just adding a method behind the scenes in order for this to work.

class Spaceship attr_acessor :destination, :name

` def cancel_launch destination = “” # just a local variable self.destination = “” # variable that can be accessed because of attr_acessor endend`

Question 2

Superclass and Subclass

Answer 2

• if you have something that’s very similar in functionality but gets really specialized then you can make a new class that inherits from the superclass.
• You can override methods in the superclass by making a method of the same name

Question 3

add functionality to the superclass method that you are overriding

Answer 3

• You can add functionality to the superclass method that you are overriding just by adding the keyword “super”

EX

class Probe def deployment(deploy_time, return_time) puts "Deploying" endend

class MineralProbe < Probe def deploy(deploy_time) puts "Preparing sample chamber" super(deploy_time, Time.now * 2 * 60 * 60) endend

MineralProbe.new.deploy(Time.now)

Question 4

Class methods and variables

Answer 4

class methods just have that self thing so you can call things on the class itself class variables aparently suck so don’t use them

Question 5

class instance variables

Answer 5

classes defined outside methods in a class only to be used and returned in a method.

EX

class Spaceship @thruster_count = 2 def self.thruster_count @thruster_count endend

Question 6

How to change characteristics/attributes defined in a superclass in its respective subclasses.

Answer 6

• define the superclass instance variable inside the subclasses

EX

class Spaceship @thruster_count = 2 def self.thruster_count @thruster_count endend

class SpritelySpaceship @thruster_count = 4end

class EconolingSpaceship @thruster_count = 1end

puts SpritelySpaceship.thruster_countputs EconolingSpaceship.thruster_countputs Spaceship.thruster_count412

Question 7

Self

Answer 7

classes are just a context and self-refers to that context. So self. on a method in a class will refer to the class. But if you put a self. inside a method in the class, it will refer to the object that the method is being called on.

EX

class Spaceship def cancel_launch self.destination = "" seatbelt_sign(:off) endend

ship.cancel_launch# the self in cancel_launch refers to the ship object, and will therefore change its destination varaible.

Question 8

Monkey Patching

Answer 8

Since classes are just a context for a workspace you can recall a class and just add to it creating new methods or overriding methods just by creating another method with the same name