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Conference noted::hackers_v1

Title:	-={ H A C K E R S }=-
Notice:	Write locked - see NOTED::HACKERS
Moderator:	DIEHRD::MORRIS

Created:	Thu Feb 20 1986
Last Modified:	Mon Aug 03 1992
Last Successful Update:	Fri Jun 06 1997
Number of topics:	680
Total number of notes:	5456

301.0. "BASIC error a little too harsh ?" by GAOV08::MAGIC (Conor Moran - Galway) Mon Sep 01 1986 15:38

	I'm sure everybody has seen this error before, but why does 
	BASIC access-violate horribly if (in immediate mode) you type

	10 dim foo(<large number>)
	run

	but 

	10 n=<large number>
	20 dim foo(n)
	run

	gives an aesthetically acceptable error message ?

	Its probably unreasonable to expect this to be allowed - I
	haven't really thought about how big an array you should be
	able to	dimension - but this error seems a little too harsh.
	The value of <large number> varies but usually >1050000 does
	the trick.

<CFM>

T.R	Title	User	Personal Name	Date	Lines
301.1	Different statements	WHYNOT::COWAN	Ken Cowan	`Mon Sep 01 1986 18:31`	13
	For questions specific to VAX BASIC see the conference CLT::VAX_BASIC (press KP7). However, while I'm here ... You have declared two different types of arrays, both of which live on the stack. In the first case, the array get allocated when you program starts, we run out of stack space and die. In the second case, the array gets allocated when the DIM gets executed -- we check the amount of stack space needed against what is available. Simple? KC
301.2	Hackers don't NEED immediate mode	SANFAN::HAYESJO	Same stuff, different Day	`Tue Sep 02 1986 09:36`	3
	;-) John
301.3		GAOV08::MAGIC	Conor Moran - Galway	`Tue Sep 02 1986 09:37`	16
	Re .-1 What I really was asking was if BASIC had to die so dramatically. The reason I mentioned it was something reminded me of this happening to a novice user back in college. Said user had only just started programming, and had never used a computer before. His first ass- ignment was to write a program which calculated all the prime numbers between 1 and 10,000 (or something like that). He got the program working O.K. after a good bit of work, and decided to experiment around. (Of course he had never been warned to take backups - Silly, but thats not the point). He modified the program to go much further, and re-Dim'ed his arrays to a size he considered adequate. Needless to say, he wasn't over-impressed when running the program resulted in some antisocial error messages, and the DCL prompt. <CFM>
301.4	Valid point, but ...	SANFAN::HAYESJO	Same stuff, different Day	`Wed Sep 03 1986 07:00`	9
	But think how excited the novice user must have been at discovering his/her "first" hack!!! (how to make BASIC spill its guts...). Seriously, Conor, I wasn't trying to belittle your concern, which is valid. I was just poking fun at the concept of putting an immediate mode BASIC problem in the 'Ackers conference. Sorry if I got your dander up. John
301.5	Oops ...	GAOV08::MAGIC	Conor Moran - Galway	`Wed Sep 03 1986 08:51`	13
	Re: .4 Actually you didn't. That reply was addressed to .1 but you slipped yours in while I was editing it (1 minute would be a pretty fast turnaround). Sorry for any confuzion John. <CFM> P.S. That'll teach me to use relative note references. I'll be a little more absolute from now on. 8^) P.P.S Whats so funny about putting an immediate mode BASIC question in a hackers notesfile ? Anybody who can get any serious work done in immediate mode MUST be a hacker.