Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!marquis@qal.qal.berkeley.edu
From: marquis@qal.qal.berkeley.edu (Roger Marquis)
Newsgroups: comp.sys.ibm.pc
Subject: QBasic null input query
Message-ID: <22071@agate.BERKELEY.EDU>
Date: 26 Mar 89 21:31:47 GMT
Sender: usenet@agate.BERKELEY.EDU
Reply-To: marquis@qal.qal.berkeley.edu (Roger Marquis)
Organization: University of California, Berkeley
Lines: 18


     How do you distinguish between a null input string (i.e., 
the return key) and a zero in QuickBasic? I've tried INKEY$, 
INPUT and INPUT$. Simply hitting return sets the value at zero
regardless of initialization or anything else I've tried. I need
to loop until an integer between zero and nine is entered. Here's 
where I'm stuck:

 NCROSS$ ="" 
 WHILE NCROSS$ = ""
      CLS : LOCATE 3, 1
      PRINT "               Input cross pattern:"
      PRINT : PRINT : PRINT
      NCROSS$ = INPUT$(1): NCROSS = VAL(NCROSS$)
 WEND
 
   Thanks in advance,
         Roger Marquis (marquis@qal.berkeley.edu)