#http://rubyquiz.com/quiz68.html
  require 'uri'
  require 'open-uri'
  require 'rexml/document'

  class Weather
    attr_reader :location, :temperature, :unit

    def initialize(zip_or_city, unit='f')
      raise "Error: Unit must be 'C' or 'F'." unless unit =~ /^[cf]$/i
      id = get_id(zip_or_city)
      url = "http://xml.weather.yahoo.com/" +
              "forecastrss/#{id}_#{unit.downcase}.xml"
      xml = open(url) { |f| f.read }
      doc = REXML::Document.new(xml)
      @temperature = 
       doc.elements['/rss/channel/item/yweather:condition/@temp'].to_s.to_i
      @unit = unit.upcase
    end

    private
      def get_id(location)
        location = URI.escape(location
        url = "http://xoap.weather.com/search/search?where=#{location}"
        xml = open(url) { |f| f.read }
        doc = REXML::Document.new(xml)
        locations = doc.elements.to_a("/search/loc")
        raise "Cannot find the location." if locations.size <= 0
        @location = locations[0].text.sub(/\s*\(\d+\)\s*$/, '')
        locations[0].attributes['id']
      end
  end

  if __FILE__ == $0
    if ARGV.size <= 0 || (ARGV[1] && ARGV[1] !~ /^[cf]$/i)
    puts "Usage: #$0 city_or_zip_code [c|f]"
    exit(1)
  end

  begin
    w = Weather.new(ARGV[0], ARGV[1] || 'f')
    puts "The temperature in #{w.location} is " +
                  "#{w.temperature} degrees #{w.unit}."
  rescue
    puts "Information for #{ARGV[0]} was not found or unavailable."
  end
  end