9.41.2.1 Special Characters

‘!’ is the line comment character.

If a ‘#’ appears as the first character of a line then the whole line is treated as a comment, but in this case the line could also be a logical line number directive (see Comments) or a preprocessor control command (see Preprocessing).

You can use ‘;’ instead of a newline to separate statements.

Since ‘$’ has no special meaning, you may use it in symbol names.