Print Calendar in Console like cal command in Mac OS X

calprint.rb

class CalendarPrinter

  @@daysOfWeek = ['Su','Mo', 'Tu','We','Th','Fr', 'Sa' ]

  def initialize(monthName, year, startDayOfMonth, daysOfMonth)
    @month = monthName
    @year = year
    @firstDayOfMonth = startDayOfMonth
    @totalDaysOfMonth = daysOfMonth
  end

  def to_s
    puts (@month + " " + @year.to_s).center((@@daysOfWeek.join(' ').length))
    puts @@daysOfWeek.join(' ')

    fdayIndex = @@daysOfWeek.index(@firstDayOfMonth)

    print '   ' * fdayIndex

    (1..@totalDaysOfMonth).each_with_index do |day, index|
      print (day).to_s.rjust(2) + ' '
      if (index+fdayIndex+1) % 7 == 0
        print "\n"
      end
    end

    print "\n"
  end

end


m = CalendarPrinter.new('March', 2014, 'Sa' ,31)
m.to_s