week_4_diagnostic.md

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.

• One difference between a module and a class is that modules can be used as mixins (mix in the methods contained within them). A module 4 student I paired with described them as a "toolbox" in that sense.

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
end

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

• Namespacing - related classes can be kept within one module
• Mixin - keep a set of tools (methods) in the module that you can "mix in" to other classes. This allows for more DRY programming, as you can share the same tools between different classes, without having to define them more than once.

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

• Only zero (0) and nil.

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

• Any integer, any string, the reserved word true

6. List 3 HTTP Verbs

• get, post, and ?

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

• HTTP Verb -

• POST

• Request Path -

• /students?name=horace

• Query Parameters -

• 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? http://127.0.0.1:9292/students?name=horace

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

• Switch to an existing branch iteration-1

• git checkout iteration-1

• Create a new branch iteration-2

• git checkout -b iteration-2 this creates it and switches to it - I don't know the command to just create it, maybe git -b iteration-2

• Push a branch iteration-2 to a remote origin

• git push origin iteration-2 if it does not exist upstream or git push if you are on the branch and it already exists

• Merge a branch iteration-1 into a branch master (assume you are not on master to begin with)

• git merge master (guessing on this one, only done it from github)

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.

• Put one of the following inside your file_two file 'require' './lib/file_one' 'require_relative' 'file_one'

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

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
end

Encryptor.new.date_offset

---

class Encryptor
  def date_offset
    date_squared = (Time.now.strftime("%d%m%y").to_i) ** 2 # here is one
    last_four_digits = date_squared.to_s[-4..-1].split('').map { |n| n.to_i  } # here is another

  end
end

Encryptor.new.date_offset