C # polymorphism 2

Sealed Classes and Methods

The variables are modified by the const and readonly keywords, indicating that these variables cannot be modified after initialization. The variables declared as const must be initialized at the declaration; variables declared as readonly can be initialized in the constructor and cannot be modified after initialization.

The keyword sealed (sealed) is applicable to methods and classes to prevent overwriting and inheritance. Methods declared as sealed cannot be overwritten in Derived classes, both static and private methods are implicitly sealed.

The use of the sealed class slightly improves the runtime performance.