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From: daver@hpsgpa.UUCP
Newsgroups: comp.sys.hp
Subject: Re: HP Basic linked lists?
Message-ID: <2790002@hpsgpa.HP.COM>
Date: Sun, 22-Feb-87 20:34:06 EST
Article-I.D.: hpsgpa.2790002
Posted: Sun Feb 22 20:34:06 1987
Date-Received: Thu, 26-Feb-87 22:48:04 EST
References: <1084@phred.UUCP>
Organization: HP Singapore IC Design Ctr
Lines: 18

Back in the days when FORTRAN was the only alternative to COBOL and assembly
language we did linked lists by using three arrays, one for each pointer and
one for the data.  In (minimal) Basic you could define three arrays, D for 
the data, N for 'next_pointer' and P for 'previous_pointer' and step through
and array forward by:
                          J=N(J)
backward by:
			  J=P(J)
and add an element after element j by:
			  P(T)=J
			  N(T)=N(J)
			  D(T)=<data>
			  P(N(T))=T
			  N(J)=T
			  T=T+1
where T points to the first unused element in the arrays.  It would also be
simple to implement a second linked list of free elements in the array to 
provide efficient use of memory when elements are removed.