backend-dev interview code example

fib.rb

class FibonacciCalculator
  def initialize
  end

  def run
    number = ARGV.first

    puts "Fibonacci number for N=#{number}: #{fib(number.to_i)}"
  end

  private
  def fib(n)
    case
      when n == 0 then 0
      when n <= 2 then 1
      else fib(n - 2) + fib(n - 1)
    end
  end
end

FibonacciCalculator.new.run