ruby_functions_practice.rb

require 'date'

def return_10
  10
end

def add(number_1, number_2)
  number_1 + number_2
end

def subtract(number_1, number_2)
  number_1 - number_2
end

def multiply(number_1, number_2)
  number_1 * number_2
end

def divide(number_1, number_2)
  number_1 / number_2
end

def length_of_string(string)
  string.length
end

def join_string(string_1, string_2)
  string_1+string_2
end

def add_string_as_number(string_1, string_2)
  string_1.to_i+string_2.to_i
end

def number_to_full_month_name(string)
  case string
  when 1
    "January"
  when 3
    "March"
  when 9
    "September"
  end
end

def number_to_short_month_name(string)
 number_to_full_month_name(string)[0..2]
end

def cube_volume(length)
  length ** 3
end

def sphere_volume(radius)
   ((4.0/3) * ((Math::PI) * (radius ** 3)))
end

def cylinder_volume(radius, height)
  ((Math::PI) * (radius ** 2) * height)
end

def rprism_volume(length, height, width)
  ((length) * (height) * (width))
end

def cone_volume(radius, height)
  (((Math::PI) * (radius ** 2)) * (height / 3.0))
end

def capsule_volume(radius, length)
  (Math::PI*(radius ** 2)) * ((4.0/3) * radius + length)
end




def days_to_christmas(date)
  christmas_date = Date.new(2015, 12, 25)
  # ((christmas_date - Date.today).to_i) - 1
  ((christmas_date - date).to_i)
end

def age(year, month, date)
  dob = Date.new(year, month, date)
  ((Date.today - dob).to_i) / 365
end

def age2(date)
  ((Date.today - date).to_i) / 365
end