When is an expression "true"?

[Peter Steele]

I wrote a simple Cshell script the other day that looked something
like this:

set f=`ls`
if $#f > 1 then
   ...
endif

In other words, I only wanted the if statement to be executed if there
was more than one file in the directory. This did not work; it went ahead
and did the body of the if statement even when there was only one file 
present. To file the problem, I added some brackets:

if ($#f > 1) then
   ...

Why are parentheses needed here? I know I've done other stuff that hasn't
needed parentheses, e.g.

if $status != 0 then
   ...

What's the story?
-- 
Peter Steele  Postmaster  peter.steele at acadiau.ca   Tel: 902-542-2201
Software Analyst, Acadia University, Wolfville, NS  Fax: 902-542-7224