week_4_diagnostic.markdown

Module 1 Week 4 Diagnostic

This exercise is intended to help you assess your progress with the concepts and techniques we've covered during the week.

For these questions, write a short description or snippet of code that meets the requirement. In cases where the question mentions a "given" data value, use the variable given to refer to it (instead of re-writing the information).

1. Give one difference between Modules and Classes.

Classes have to be instantantiated to be used, Modules cannot be instantiated.

2. Defining Modules

First, create a module Doughy which defines a method has_carbs? that always returns true. Then, given the following Pizza class, update Pizza to use your new Doughy module to gain the defined has_carbs? behavior.

module Doughy
  def has_carbs?
    true
   end
end

class Pizza

include Doughy

  def tasty?
    true
  end
end

3. What are two benefits modules provide us in Ruby? Elaborate on each.

Modules can be used to hold methods that will be used in multiple classes. A module's methods can be used across classes. This is a powerful tool to reduce repetition.

Modules can also be used for namespacing but I'm still not exactly sure what the benefits of that are.

4. What values in Ruby evaluate as "falsy"?

nil, false

5. Give 3 examples of "truthy" values in Ruby.

true, strings, integers

6. List 3 HTTP Verbs

get, post, ??? delete?

7. HTTP Parsing: given the following HTTP Request, identify the following:

•   HTTP Verb
•   Request Path
•   Query Parameters  

POST

/students?

name=horace

POST /students?name=horace HTTP/1.1
Host: 127.0.0.1:9292
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8

What is the full request URL?

\n127.0.0.1:9292/students?name=horace

8. Git and Branches: give a git command to accomplish each of the following:

• Switch to an existing branch iteration-1
• Create a new branch iteration-2
• Push a branch iteration-2 to a remote origin
• Merge a branch iteration-1 into a branch master (assume you are not on master to begin with)

git checkout iteration-1

git branch iteration-2

git push origin iteration-2

git merge master

9. Load Paths and Requires

Given a project with the following directory structure, give 2 ways that we could require file_one from file_two.

. <you are here>
├── lib
│  │── file_one.rb
│  └── file_two.rb

require './lib/file_one'

require_relative 'file_one'

10. Refactoring: given the following snippet of code, show 2 refactorings you might make to improve the design of this code.

class Encryptor
  def date_offset
    date = Time.now.strftime("%d%m%y").to_i
    date_squared = date ** 2
    last_four_digits = date_squared.to_s[-4..-1]
    [last_four_digits[-4].to_i,
    last_four_digits[-3].to_i,
    last_four_digits[-2].to_i,
    last_four_digits[-1].to_i]
  end

  def date_offset_refactor
     date = Time.now.strftime("%d%m%y").to_i
    (date ** 2).to_s[-4..-1].chars.map { |number| number.to_i}
  end
end


Encryptor.new.date_offset_refactor