|Don't ask to ask, just ask|
(almost) Never One - it requires too much brain work to figure out what's going on when scanning through code.
Never three - all that is seen is the condition; the action gets lost.
Most often Two. The action is obvious and generally the most important thing. If the condition is really important I'd:
to make the condition obvious and the action easy to find.
As a general rule stuff at the end of a long or complicated line will tend to be ignored. If it's important it be seen don't stick it on the end of a line.
True laziness is hard work
In reply to Re: A matter of style: how to perform a simple action based on a simple condition?