Class HourlyEmployee Employee hourlyRate numberOfHours
Methods HourlyEmployee 
   new
      super new.
      self rate: 0.
      self setHours: 0.
      ^self
|
   salary
      ^hourlyRate * numberOfHours
|
   rate: aRate
      hourlyRate <- aRate.
|
   setHours: numHours
      numberOfHours <- numHours.
|
   addHours: numHours
      numberOfHours <- numberOfHours + numHours.
]