In inheritance, we can assign the child class to the parent class without casting but we can’t assign a parent class to the child class without using casting. Consider the following example ...

The example in Figure 1 illustrates single inheritance ... and hovercraft. Child classes inherit accessible fields and methods from their parent classes and other ancestors. They never inherit ...

Sealed classes address precisely the type of inheritance control previously described. Here's how we can refactor the above example: public sealed class Transaction permits StockTransaction, ...