cia_world_factbook.rb

require 'nokogiri'

class CIAFacts
  def initialize(xml_file = 'cia-1996.xml')
    @doc = Nokogiri::XML(File.open(xml_file))
  end
  
  def country_with_most_people
    node = @doc.xpath("//country/attribute::population").max_by { |x| x.text.to_i }
    [node.parent['name'], node.text]
  end
  
  def five_highest_inflation_rates
    nodes = @doc.xpath("//country/attribute::inflation").
      sort_by { |node| -node.text.to_i }.take(5)
    
    nodes.inject([]) { |acc, node| acc << [node.parent['name'], node.text] }
  end
  
  def continents_list
    nodes = @doc.xpath("//country/attribute::continent")
    hash = Hash.new { |hash, key| hash[key] = [] }
    nodes.each { |node| hash[node.text] << node.parent['name'] }
    hash
  end
end

cia_world_factbook_spec.rb

require 'cia_world_factbook'

describe "CIAFacts" do
  before do
    @cia = CIAFacts.new
  end
  
  it "should get country with most people" do
    actual = @cia.country_with_most_people
    actual.should == ['China', '1210004956']
  end
  
  it "should get five highest inflation rates" do
    actual = @cia.five_highest_inflation_rates
    actual.length.should == 5
    actual[0].should == ['Belarus', '244']
    actual[1].should == ['Turkey', '94']
    actual[2].should == ['Azerbaijan', '85']
    actual[3].should == ['Malawi', '83.3']
    actual[4].should == ['Yemen', '71.3']
  end
  
  it "should get continents and countries" do
    actual = @cia.continents_list
    actual.keys.length.should == 6
    actual.values.flatten.count.should == 260
    actual.keys.sort.should == ['Africa', 'Asia', 'Australia/Oceania', 'Europe', 'North America', 'South America']
    actual['Africa'][3].should == 'Benin'
    actual['Asia'][3].should == 'Azerbaijan'
    actual['Australia/Oceania'][5].should == 'Fiji'
    actual['Europe'][2].should == 'Austria'
  end
end

report.rb

require 'cia_world_factbook'

def print_report(cia)
  puts "CIA WORLD FACTBOOK 1996".center(80, '-')
  
  data = cia.country_with_most_people    
  puts wrap("The country with most people is #{data.first} and " + 
            "it's population is #{data.last}", 75, 2)
  
  data = cia.five_highest_inflation_rates
  puts wrap("The five highest inflation rates are:", 75, 2)
  data.each do |datum|
    puts wrap("#{datum.first} with an infletion of #{datum.last}", 75, 4)
  end
  
  data = cia.continents_list
  puts wrap("Continents and countries:", 75, 2)
  data.sort.each do |continent, countries|
    puts wrap("#{continent}:", 75, 4)
    puts wrap(countries.sort.join(", "), 75, 6)
  end
  
  puts "#{'-' * 80}"
end

def wrap(str, width=80, spaces=0)
  lines, line = [], ""
  
  str.split(/\s+/).each do |word|
    if line.size + word.size >= width
      lines << "#{' ' * spaces}#{line}"
      line = word
    elsif line.empty?
      line = word
    else
      line << ' ' << word
    end
  end
  lines << "#{' ' * spaces}#{line}" if line
  
  lines.join("\n")
end

print_report(CIAFacts.new)