mkweick

class Luhn
  attr_reader :cd, :luhn, :luhn_sum
  
  def initialize(num, create = nil)
    @luhn = num.to_s.split('').map(&:to_i)
    @cd = luhn.pop unless create
  end
  
  def addends
    num = (luhn.size - 1)

mkweick

class Sieve
  attr_reader :max, :range
  
  def initialize(max)
    @max = max
    @range = {}
    (2..max).each { |n| range[n] = 1 }
  end
  
  def primes

mkweick

class Series
  attr_reader :series
  
  def initialize(series)
    @series = series
  end
  
  def slices(slice)
    valid?(slice)
    last_valid_index = series.length - slice

mkweick

1.) index, new, create, show, edit, update, delete
    GET, POST, PATCH/PUT, DELETE
    GET    '/photos',           to: photos#index 
    GET    '/photos/new,        to: photos#new
    POST   '/photos,            to: photos#create
    GET    '/photos/:id',       to: photos#show
    GET    '/photos/:id/edit',  to: photos#edit
    PATCH  '/photos/:id',       to: photos#update
    DELETE '/photos/:id',       to: photos#delete
    "can use  as: 'something' to create a custom named route"

mkweick

class Board
  
  def self.transform(input)
    output = []
    fail ValueError unless valid_game?(input)
    input.each_with_index do |row, row_index|
      if row_index == 0 || row_index == (input.size - 1)
        output << row
      else
        output_row = ''

mkweick

1.) Data is stored in tables in a manner where it can retrieved by a unique ID (primary ID)
    and can be related to data in other tables via foreign key.

2.) Structured Query Language is language used to interact with relational databases

3.) schema view --> structure of the table (column name, column type, PK, FK, etc...)
    data view ----> actual data in columns from the table

4.) Primary Key

mkweick

class Robot
  attr_accessor :bearing, :coordinates
  
  def orient(direction)
    if [:north, :east, :south, :west].include? direction
      self.bearing = direction
    else
      raise ArgumentError, "Invalid direction"
    end
  end

mkweick

class Cipher
  VALUES = [('a'..'z').to_a, (0..25).to_a].transpose.to_h
  attr_reader :key
  
  def initialize(key = new_key)
    @key = key
    raise_error_conditions
  end
  
  def encode(msg)

mkweick

class Triplet
  attr_reader :a, :b, :c
  
  def initialize(a, b, c)
    @a = a
    @b = b
    @c = c
  end
  
  def sum