require 'rexml/node'
 require 'rexml/element'
 require 'rexml/document'
 require 'rexml/encoding'
 include REXML

 #Open an existing XML file.
 file = File.new("example1.xml","r")
 doc = REXML::Document.new(file)

 cardatabase = doc.root

 #add an attribute to each car
 cardatabase.each_element { |car|
   car.add_attribute( "owner", "Dennis")
 }

 #show the owner of each car
 puts "Dennis owns: "
 cardatabase.each_element { |car|
   if(car.attributes['owner'] == "Dennis")
     puts car.attributes['make']
   end
 }

 #find the make of the 'Yellow' car
 puts
 puts "The yellow car is the " + cardatabase.elements["car[@color='Yellow']"].attributes['make']

 #change the 'owner' attribute
 puts
 puts "Select a car: "
 make = gets.chomp
 if(cardatabase.elements["car[@make='#{make}']"] != nil)
   puts "Give the #{make} to: "
   name = gets.chomp
   cardatabase.elements["car[@make='#{make}']"].attributes['owner'] = name
   puts "The owner of the #{make} is now " + cardatabase.elements["car[@make='#{make}']"].attributes['owner']
 else
   puts "The #{make} was not found."
 end

 file2 = File.new("example2.xml","w")
 file2.write(doc)