The Common Type System (CTS) defines how types are declared, used, and managed in the runtime.

It is an important for Language Interoperability.

The CTS performs the following functions:

·    Establishes a common framework that enables cross-language integration, type safety, and high performance code execution.

·    Provides an object-oriented model.

·    Defines rules that languages must follow, so that different languages can interact with each other. 

Classification of types

The CTS supports two categories:

1. Value types

2. Reference types

Value types directly stores data in the variable. Value types can be built-in type, user-defined types, or enumerations.

Reference types store a reference to the data’s memory address. Reference types can be self describing types, pointer types, or interface types. Self-describing types are further split into arrays and class types. The class types are user-defined classes, boxed value types, and delegates.

All types derive from the System.Object base type.