g1na1011/c1wk2_quiz.md

## c1wk2_quiz.md

      
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    Week 2 Quiz


Name what each of the below is:

  a = 1 
  # => ex. a is a local variable, and is a Fixnum object with value 1
  
  @a = 2 
  # => @a is an instance variable, and is a Fixnum object with value 2
  
  user = User.new 
  # => user is a new instance object of the class User
  
  user.name 
  # => the object user is calling the name getter instance method
 
 user.name = "Joe" 
 # => the object user is calling the name setter instance method, resetting the object's name string value to "Joe"


How does a class mixin a module?
module ModExample
  # code for module here
end

class Animal
  include ModExample
  
  # code for class here
end


What's the difference between class variables and instance variables?
Answer: A class variable is shared among the class and all of its descendants. It also begins with two @@ symbols. An instance variable is not shared by the class' descendants and it begins with one @ symbol.


What does attr_accessor do?
Answer: attr_accessor is a shortcut to define a class' getter and setter methods.
class Dog
  attr_accessor :name
end

# This is the same without using 'attr_accessor'. 
class Dog
  def name
    @name
  end
  
  def name=(new_name)
    @name = new_name
  end
end


How would you describe this expression: Dog.some_method
Answer:
The class Dog is calling a class method called some_method.


In Ruby, what's the difference between subclassing and mixing in modules?
Answer:
Subclassing is when the classes is a relationship and has a single inheritance. For example, a Dog subclass will inherit all of the behaviors of  an Animal superclass.
Mixing in modules is called composition and it is when classes has a relationship. This is usually when classes have multiple inheritances or when certain behaviors are shared among classes, but not every single one of them.


Given that I can instantiate a user like this: User.new('Bob'), what would the initialize method look like for the User class?
class User
     attr_accessor :name
   
  def initialize(name)
    self.name = name
  end
end


Can you call instance methods of the same class from other instance methods in that class?
Answer: Yes, you may call instance methods of the same class from other methods in that class.


When you get stuck, what's the process you use to try to trap the error?
Answer: Use the pry gem to debug your code. Insert binding.pry to each of the sections in your code that you wish to debug. Trap the error by eliminating the non-problematic areas.
require "pry"

# Ruby code
# Ruby code


=> Put "binding.pry" wherever you would like debugging to start.

=> CTRL+D in your terminal will continue the execution. Remove "binding.pry" when done.

binding.pry
Ruby code

Ruby code