Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!uwvax!astroatc!nicmad!brown
From: brown@nicmad.UUCP (Vidiot)
Newsgroups: comp.sys.ibm.pc
Subject: Re: QBasic null input query
Message-ID: <3822@nicmad.UUCP>
Date: 1 Apr 89 04:18:36 GMT
References: <22071@agate.BERKELEY.EDU>
Reply-To: brown@nicmad.UUCP (Vidiot)
Distribution: na
Organization: Vidiot's Hangout
Lines: 39

In article <22071@agate.BERKELEY.EDU> marquis@qal.qal.berkeley.edu (Roger Marquis) writes:
<
<     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

Your problem is that if you are looking for for one of the zero through nine
keys to be pressed, either from the top row, or from the numeric keypad, you
aren't going to find it that way.  Why, because the press of the RETURN key
will give you zero, as well as pressing the zero key.  You need to look for
the ASCII character:


NCROSS$ ="" 
WHILE NCROSS$ < "0" OR NCROSS$ > "9"
     CLS : LOCATE 3, 1
     PRINT "               Input cross pattern:"
     PRINT : PRINT : PRINT
     NCROSS$ = INPUT$(1)
WEND


Try that, it should be better.
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