Week_2_and_3_Diagnostic

diagnostic.markdown

Define a class called PizzaOven which has a method cook_pizza which returns the string "mmm 'za".

class PizzaOven

  def cook_pizza
    "mm za"
  end

end

Define a class called Student which is instantiated with a “name” value and which has a method name that returns this value

class Student

  def initialize(name)
    @name = name
  end

  def name
    @name
  name

end

Given an array of the numbers [1,2,3,4,5], find the sum of the doubles of all the numbers

sum = 0
numbers = [1,2,3,4,5]

numbers.each do |number|
  sum += number * 2
end

Give the command to create a new Git repository in a directory on your machine

git init
git remote add origin github_url
git push -u origin

Pizza

Given a hypothetical Pizza class which has an instance method is_tasty? that always returns true, write a simple Minitest test that tests this behavior.

class PizzaTest < Minitest::Test

def test_is_tasty_always_true
  pizza_1 = Pizza.new
  assert_equal true, pizza_1.is_tasty?
end

Suppose the Pizza class also has a method style which randomly returns one of: "supreme", "mediterranean", or "cheese". Write a test that confirms that the returned pizza style is within this list.

class PizzaTest < Minitest::Test
  def test_pizza_is_one_of_3_styles
    pizza_1 = Pizza.new
    assert_equal "supreme" || "mediterranean" || "cheese", pizza_1.style
  end

Give the Git commands needed to stage and then commit a set of changes to a file

git add .
git commit

Student

Define a Student class which, when created, has an attitude attribute. attitude should start out with the value “cheerful”, and the Student class should provide a “reader” method that allows us to access the value of its attitude.

Additionally, add an assign_homework method to Student. When assigned_homework is invoked, if the student’s attitude is "cheerful", it should become "dubious". If the value is currently "dubious" it should become "perturbed". If the value is currently "perturbed", it should become "dazed". Assigning homework to a "dazed" student has no effect.

Building on the Student class from the previous example, update the assign_homework method to accept an argument. The argument will be a String containing a short description of the assignment. For example we might use it like this:

s = Student.new s.assign_homework("Write a linked list") Then, add an assignments method to Student. assignments should return a list of all the assignments that have been given, separated by a comma and a space. For example:

s = Student.new s.attitude => "cheerful" s.assign_homework("write a linked list") s.attitude => "dubious" s.assign_homework("write a BST") s.attitude => "perturbed" s.assignments => "write a linked list, write a BST" Given an array of 3 Student instances, generate a new string of all of their assignments For example:

s1 = Student.new s2 = Student.new s3 = Student.new

s1.assign_homework("linked list") s1.assign_homework("sorting algos")

s2.assign_homework("write a c compiler") s2.assign_homework("write a pacman game")

s3.assign_homework("headcount") s3.assign_homework("sales engine")

students = [s1,s2,s3]

=> "linked list, sorting algos, write a c compiler, write a pacman game, headcount, sales engine"

class Student
  attr_accessor :attitude,
                :homework_list

  def initialize(attitude = "cheerful")
    @attitude = attitude
    @homework_list = []
  end

  def assign_homework(homework)
    @homework_list << homework
      if @homework_list.length == 1
        @attitude = "dubious"
      elsif @homework_list.length == 2
        @attitude = "perturbed"
      elsif @homework_list.length >= 3
        @attitude = "dazed"
      end
  end
end

nick = Student.new
jack = Student.new
danny = Student.new

nick.assign_homework("linked list")
nick.assign_homework("sorting algos")

jack.assign_homework("write a c compiler")
jack.assign_homework("write a pacman game")

danny.assign_homework("headcount")
danny.assign_homework("sales engine")

students = [nick, jack, danny]

homework = students.map do |student|
  student.homework_list
end

print homework.join(", ")

What does the following code output?

def print_variables(x) puts "x: #{x}" puts "b: #{b}" end

def b 12 end

a = 4 print_variables(a)

x: 4
b: 12

Working with files: given a text file located at "~/Documents/pizza.txt", write code to read the file from the filesystem and print each line one at a time.

I'm still pretty shakey on this

puts File.open("~/documents/pizza.txt).readlines


???

Writing Files: given a text file located at "/Documents/pizza.txt", write code to read the file from the filesystem, then write a new file at "/Documents/line_count.txt" containing the number of lines in the original file.

Imagine a simple ruby class designed to represent a Corgi dog. Write a test for each of the following features:

A Corgi can be created with no arguments A Corgi can be assigned a name A Corgi can be asked for its name A Corgi can be asked for its posture, which should default to “standing” A Corgi can be asked to lie down, which should change its posture to “laying”

def test_can_be_created_with_no_arguments
  assert Corgi.new
end

def test_can_be_assigned_a_name
  corgi_1 = Corgi.new("Sputnik)
  assert_equal "Sputnik", corgi_1.name
end

def test_corgi_posture
  corgi_1 = Corgi.new("Mir")
  assert_equal "standing", corgi_1.posture
end

def test_corgi_lay_down
  corgi_1 = Corgi.new("Voyager")
  corgi_1.lie_down
  assert_equal "laying", corgi_1.posture
end