What are the purposes of C language identifiers?

C language identifiers are primarily used to represent the names of variables, functions, arrays, structures, enumerations, and other entities. Their purposes include:

1. Variable name: Identifiers can be used to name variables, which store data.
2. Function name: Identifiers can be used to name functions, which are used to encapsulate a specific program logic.
3. Array name: an identifier used to name an array, which stores a series of data of the same type.
4. Struct names: identifiers can be used to name a struct, defining a data structure that includes multiple different data types.
5. Enumerate constant names: Identifiers can be used to name constants in enumeration types, defining a finite set of values.
6. Macro definition name: An identifier can be used to name a macro definition, which is used to replace text in a program.
7. Tag names: Identifiers can be used to name tags, used to label within loop or jump statements.

In short, identifiers in the C language are used to name various entities, making programs easier to read and understand, while also increasing code maintainability and reusability.