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Sealing Virtual Members

Recall that the sealed keyword can be applied to a class type to prevent other types from extending

its behavior via inheritance. As you may remember, we sealed PTSalesPerson as we assumed it

made no sense for other developers to extend this line of inheritance any further.

On a related note, sometimes you may not wish to seal an entire class, but simply want to pre-

vent derived types from overriding particular virtual methods. For example, assume we do not want

part-time salespeople to obtain customized bonuses. To prevent the PTSalesPerson class from over-

riding the virtual GiveBonus() method, we could effectively seal this method in the SalesPerson

class as follows: