The Common Type System defines how types are DECLARED, USED, and managed in the common LANGUAGE runtime, and is also an IMPORTANT part of the runtime's support for cross-language integration.

Here we have several languages and each and every language has its own data type and 1 language data type cannot be understandable by other languages.

CTS is a specification created by Microsoft and included in the European COMPUTER Manufacturer‘s Association standard. It has certain standard features for implementing the .NET framework.

There are different types which CTS Support:

1. Value Types: It directly contains the data and instances are either allocated on the stack or allocated inline in a structure. Value types can be built-in, user-defined or enumerations types.
2. Reference Types: Value’s memory address reference are stored and are allocated on the heap. This can be any of the pointer types, interface types or self-describing types.

Operations on variables of a value type do not affect any other variable, whereas, operations on variables of a reference type can affect the same object referred to by another variable.