9.42.3.1 Special Characters

A ‘!’ character appearing anywhere on a line indicates the start of a comment that extends to the end of that line.

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).

‘;’ can be used instead of a newline to separate statements.