refactored

class Tournament

  def initialize
    @players = []
  end

  def add_player(player)
    @players << player
  end

  def sort_players
    @players.sort!{|p1, p2| p1.score <=> p2.score}.reverse!
  end

  def to_s
    str =  "Average rating is: #{average_rating}\n"
    @players.each do |p|
      str += p.to_s
      str += " AVG OPPONENT RATING: #{p.get_rating}"
      str += " TOTAL: #{p.score} points"
      str += " NEW RATING: #{new_rating(p).to_i}\n"
    end
    str
  end

  private

  def total_rating
    total_rating = 0
    @players.each{|p| total_rating += p.get_rating}
    total_rating
  end

  def average_rating
    total_rating / @players.size
  end

  def average_opponent_ratings(curr_player_rating)
      (total_rating - curr_player_rating) / (@players.size - 1)
  end

  def expected_score_per_round(player)
    1.0 / (1.0 + 10.0**((average_opponent_ratings( player.get_rating ) - player.get_rating ) / 400.0) )
  end

  def new_rating(player)
    player.get_rating + 40 * ( player.score * 1.0 - ( ( @players.size - 1) * expected_score_per_round(player)))
  end

end

class Player

  def initialize(name, rating, results)
    @name = name
    @rating = rating
    @results = results
  end

  def get_rating
    @rating
  end

  def score
    @results.inject(0) { |sum,val| sum += val }
  end

  def to_s
    str = @name + " #{@rating} "
    @results.each {|r| str+=" #{r}"}
    str
  end

end

t = Tournament.new
file = File.new('tournament_results.txt', "r")
while (line = file.gets)
  data =  line.split # so data is an array of strings
  name = data[0]
  rating = data[1].to_i
  results = []
  data[2..data.length].each_with_index{|res,i| results[i]=res.to_i}
  p = Player.new(name, rating, results)
  t.add_player(p)
end
t.sort_players
puts t.to_s