What is the function of the sealed keyword when applied to a class?

The sealed keyword is a specific feature in object-oriented programming, particularly in languages like C# that support this concept. When applied to a class, it serves to restrict inheritance. This means that no other class can derive from a sealed class.

The main purpose of using the sealed keyword is to ensure that the implementation of a class remains unchanged and unmodified by any subclasses. This can be important for maintaining the integrity of critical logic, performance optimization, or security concerns where the class behavior should remain predictable and controlled.

In summary, marking a class with the sealed keyword effectively prevents other classes from inheriting from it, thus ensuring that the class acts as a complete, final version of the implementation for that functionality.