Unary operators should not be separated from their single operand.
Generally, all binary operators
except
`.'
and
`->'
should be separated from their operands by blanks.
Some judgement is called for in the case of complex expressions,
which may be clearer if the ``inner'' operators are not surrounded
by spaces and the ``outer'' ones are.
If you think an expression will be hard to read, consider breaking it across lines. Splitting at the lowest-precedence operator near the break is best. Since C has some unexpected precedence rules, expressions involving mixed operators should be parenthesized. Too many parentheses, however, can make a line harder to read because humans aren't good at parenthesis-matching.
There is a time and place for the binary comma operator,
but generally it should be avoided.
The comma operator is most useful
to provide multiple initializations or operations,
as in for statements.
Complex expressions,
for instance those with nested ternary
?:
operators,
can be confusing and should be avoided if possible.
There are some macros like
getchar
where both the ternary
operator and comma operators are useful.
The logical expression operand before the
?:
should be parenthesized and both return values must be the same type.