Define function plu(n) that returns '' (an empty string) if n=1, or 's' otherwise. This is handy for displaying messages from a program. For example,

   disp([num2str(n) ' point' plu(n) ' removed'])

produces

   0 points removed
   1 point removed
   2 points removed

etc., which is a little nicer than the typical alternative

   0 point(s) removed
   1 point(s) removed
   2 point(s) removed

and infinitely better than

   0 points removed
   1 points removed
   2 points removed