Sealed classes are used to restrict the inheritance feature of object oriented programming. Once a class is defined as a sealed class, this class cannot be inherited.
In C#, the sealed modifier is used to declare a class as sealed. If a class is derived from a sealed class, compiler throws an error.
If you have ever noticed, structs are sealed. You cannot derive a class from a struct.
The following class definition defines a sealed class in C#:
sealed class SealedClass