Identifiers in the C Programming Language



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In the C programming language, identifiers are names used to identify variables, functions, types, labels, and other entities in a program. Here are some important rules and conventions regarding identifiers in C:

Naming Rules

  • Identifiers must begin with a letter (A-Z or a-z), an underscore (_), or a currency character ($).
  • After the initial character, identifiers can contain letters, digits (0-9), underscores, or currency characters.
  • Identifiers are case-sensitive, so myVariable and myvariable are treated as different identifiers.

Length Limitation

C does not impose a specific limit on the length of an identifier, but the first 31 characters are significant. Identifiers longer than 31 characters may cause portability issues.

Reserved Words

C has a set of reserved words, also known as keywords, that have predefined meanings in the language and cannot be used as identifiers. Examples include if, while, int, void, etc.

Good Naming Practices

  • Choose meaningful and descriptive names for identifiers to enhance code readability.
  • Use camel case or underscore-separated naming conventions. For example, myVariable, someFunction, or user_name.
  • Avoid using reserved words or library function names as identifiers to prevent conflicts and confusion.


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