rpcfn13.rb

require "rexml/document.rb"
include REXML
XMLFILE = "cia-1996.xml"

class CIAFile1996
  
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  # Parse xml file and create instance variable @world (REXML::Element), 
  # which we will use throughout our class methods.
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  def initialize
    xmlfile = File.new(XMLFILE)
    doc = Document.new xmlfile
    @world = doc.root
  end
  
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  # This method searches country with the highest population and returns
  # result in the form of an array with 2 objects (first object is String 
  # object representing name of the country, while second object is Integer
  # (actually Bignum...) object representing population number for that country).
  #
  # Example:
  #   max_population = ["China", 1210004956]
  #
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  def highestPopulationCountry
    max_population = ["country name", 0]
    @world.elements.each { |country|
        if country.attributes["population"].to_i > max_population[1].to_i
          max_population[0] = country.attributes["name"]
          max_population[1] = country.attributes["population"].to_i
        end
    }
    return max_population
  end
  
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  # This method first creates Hash collection containing countries (keys) and 
  # their inflation rates (values). It then sorts Hash by element values, and 
  # then creates Array object with [country_name, inflation_value] element pairs.
  #
  # Example:
  #   a[0] = ["Belarus",244.0]
  #   a[1] = ["Turkey",94.0]
  #   ...
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  def topHighestInflationRates(nr)
    temp_arr = Hash.new
    @world.elements.each { |country|
      if country.attributes["inflation"]
        temp_arr[country.attributes["name"]] = country.attributes["inflation"].to_f
      end
    }
    temp_arr = temp_arr.sort{|a,b| b[1]<=>a[1]}
    a = Array.new
    counter = 0
    temp_arr.each { |country, value|
      (counter+=1)>=(nr+1) ? break : a.push([country, value])
    }
    return a
  end
  
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  # This method creates Hash collection with key values representing continets
  # names. Values of Hash elements are arrays with String objects representing
  # country name. Arrays are sorted alphabetically.
  #
  # Example:
  #   a["Africa"] = ["Algeria", "Angola", "Bassas da India" ... etc]
  #   a["Europe"] = ["Albania", "Andorra", "Austria" ... etc]
  #   ...
  #
  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
  def listCountriesByContinent
    a = Hash.new
    @world.elements.each{ |country|
      if country.attributes["continent"]
        if a[country.attributes["continent"]].class == Array
          a[country.attributes["continent"]].push(country.attributes["name"])
        else
          a[country.attributes["continent"]] = Array.new
          a[country.attributes["continent"]].push(country.attributes["name"])
        end
      end
    }
    a.each { |continent, countries|
      countries.sort!
    }
    return a
  end

end

test_rpcfn13.rb

require "rpcfn13.rb"
require "test/unit.rb"

class REXMLParseTest < Test::Unit::TestCase
  
  @@xmlFile = CIAFile1996.new
  
  def test1
    puts "Testing highestPopulationCountry method..."
    a = @@xmlFile.highestPopulationCountry
    assert_equal "China", a[0]
    assert_equal 1210004956, a[1]
  end
  
  def test2
    puts "Testing topHighestInflationRates method..."
    a = @@xmlFile.topHighestInflationRates(5)
    assert_equal "Belarus", a[0][0]
    assert_equal 244.0, a[0][1]
    assert_equal "Turkey", a[1][0]
    assert_equal 94.0, a[1][1]
    assert_equal "Azerbaijan", a[2][0]
    assert_equal 85.0, a[2][1]
    assert_equal "Malawi", a[3][0]
    assert_equal 83.3, a[3][1]
    assert_equal "Yemen", a[4][0]
    assert_equal 71.3, a[4][1]
  end

  def test3
    puts "Testing listCountriesByContinent method..."
    a = @@xmlFile.listCountriesByContinent
    assert a["Africa"].include?("Morocco")
    assert a["Europe"].include?("Serbia and Montenegro")
    assert a["South America"].include?("Chile")
    assert a["Australia/Oceania"].include?("Niue")
    assert a["North America"].include?("Clipperton Island")
    assert a["Asia"].include?("Russia")
    assert_equal "Algeria", a["Africa"][0]
    assert_equal "Albania", a["Europe"][0]
    assert_equal "Argentina", a["South America"][0]
    assert_equal "American Samoa", a["Australia/Oceania"][0]
    assert_equal "Anguilla", a["North America"][0]
    assert_equal "Afghanistan", a["Asia"][0]
    assert_equal 260, a["Africa"].length + a["Europe"].length + a["South America"].length + a["Australia/Oceania"].length + a["North America"].length + a["Asia"].length
    assert_equal 6, a.keys.length
  end
end