visitor2.rb.rb

class Table
  
  attr_reader :num_diners, :table_no
  
  def initialize table_no, num_diners
    @table_no = table_no
    @num_diners = num_diners
  end
  
  def to_string
    "Table #{@table_no} has #{@num_diners} diners"
  end
  
  def contented? 
    if rand(2) > 0
      return true
    else
      return false
    end
  end
  
end


class Waiter
  def initialize tables
    @tables = tables
  end
end

class CountingWaiter < Waiter
  
  attr_reader :no_of_diners

  def count_diners
    @no_of_diners = 0
    @tables.each { |table| @no_of_diners += table.num_diners}
  end
end

class ContentmentWaiter < Waiter
  
  attr_reader :unhappy_tables
  
  def get_unhappy_tables 
    @unhappy_tables = []
    @tables.each do |table| 
      if !table.contented?
        @unhappy_tables << table.table_no
      end
    end
  end
end



# create 10  tables
tables = []
1..10.times do |i|
  tables << Table.new(i, rand(3) + 2)
end
tables.each { |t| puts t.to_string}

# counting waiter goes to each table and adds up number of diners
waiter = CountingWaiter.new tables
waiter.count_diners
puts "Total number of diners: #{waiter.no_of_diners}"

# contentment waiter goes to each table and stores table number of all unhappy tables
waiter = ContentmentWaiter.new tables
waiter.get_unhappy_tables
puts "Unhappy tables: #{waiter.unhappy_tables}"