### Lexical Elements - Tokens

Source code is treated during preprocessing and compilation as a sequence of tokens. There are five different types of tokens:

- Identifiers
- Keywords
- Literals
- Operators
- Other separators

Adjacent identifiers, keywords and literals must be separated with white space. Other tokens should be separated by white space to make the source code more readable. White space includes blanks, horizontal and vertical tabs, new lines, form feeds and comments.

Lexical Elements of C - Comments
Lexical Elements - Identifiers
Lexical Elements - Constants