class Float
  alias precisionless_round round
  private :precisionless_round

  # Rounds the float with the specified precision.
  #
  #   x = 1.337
  #   x.round    # => 1
  #   x.round(1) # => 1.3
  #   x.round(2) # => 1.34
  def round(precision = nil)
    if precision
      magnitude = 10.0 ** precision
      (self * magnitude).round / magnitude
    else
      precisionless_round
    end
  end
end if RUBY_VERSION < '1.9'