This was a challenge as posted on reddit: http://www.reddit.com/r/dailyprogrammer/comments/1undyd/010714_challenge_147_easy_sport_points/ The challenge: You must write code that verifies the awarded points for a fictional sport are valid. This sport is a simplification of American Football scoring rules. This means that the score values must be …

sports_scoring.rb

# 6 points for a "touch-down"
# 3 points for a "field-goal"
# 1 point for an "extra-point"; can only be rewarded after a touch-down. Mutually-exclusive with "two-point conversion"
# 2 points for a "two-point conversion"; can only be rewarded after a touch-down. Mutually-exclusive with "extra-point"

class Scoring

  attr_reader :max_number_each, :scoring_values
  attr_accessor :score, :counter

  def initialize(score)
    check_input(score)
    @scoring_values = [3, 6, 7, 8]
    @counter = Array.new(4, 0)
    @max_number_each = get_max_values(score)
    @valid = nil
    check_if_equal(score)
  end

  def check_input(score)
    raise ArgumentError if score.class != Fixnum
  end

  def get_max_values(score)
    self.scoring_values.map { |point_value| check_max(point_value, score) }
  end

  def check_max(points, score)
    score / points
  end

  def roll_over?
    @counter.each_with_index do |counter_num, index| 
      if counter_num > self.max_number_each[index]
        return @valid = false if index == 3
        @counter[index] = 0
        return @counter[(index + 1)] += 1
      end
    end
    @counter[0] += 1  
  end

  def scoring_play_to_points(num_scoring_plays, index)
    self.scoring_values[index] * num_scoring_plays
  end

  def calculated_points
    @counter.map.with_index {|each_scoring_play, sindex| scoring_play_to_points(each_scoring_play, sindex)}.reduce(:+)
  end

  def valid_score?(score)
    return @valid = true if calculated_points == score
  end

  def check_if_equal(score)
    
    while @valid.nil?
      valid_score?(score)
      roll_over?
    end
    puts(@valid ? "Valid Score" : "Invalid Score")
  end
end

puts Scoring.new(5)
puts Scoring.new(25)