Warm-Up 09-21-15

clock.rb

# http://exercism.io/exercises/ruby/clock/readme

class Clock
  def self.at(hours=0, minutes=0)
    new(hours, minutes)
  end

  def initialize(hours=0, minutes=0)
    array = minutes.divmod 60

    @minutes = array[1]
    @hours = array[0] + hours
  end

  def to_s
    hour_string = @hours.to_s.rjust(2, "0")
    minute_string = @minutes.to_s.rjust(2, "0")
    "#{hour_string}:#{minute_string}"
  end

  def + minutes
    @minutes += minutes
    num, @minutes = @minutes.divmod 60
    @hours = num + @hours
    @hours = @hours % 24
    self
  end

  def - minutes
    @minutes -= minutes
    num, @minutes = @minutes.divmod 60
    @hours = num + @hours
    @hours = @hours % 24
    self
  end

end