Source code is treated during preprocessing and compilation as
a sequence of
tokens. A token is the smallest independent unit of meaning
in a program, as defined by the compiler. There are four different types of
tokens:
- Keywords
- Identifers
- Literals
- Punctuators and operators
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.