Each and Map

Burgers.rb

require 'pry'
array = [1,2,3]

class Array

  def hamburger(&block)
    i = 0
    while i < self.length
      yield(self[i])
      i += 1
    end
   return self
  end

  def cheeseburger(&block)
    result = []
    i = 0
    while i < self.length
      result << yield(self[i])
      i += 1
    end
   return result
  end

end

new_array = array.cheeseburger { |x| x ** 2 }

puts new_array