'nil' and 'leaf' are arbitrary symbols. 'nil' is the standard symbol used to terminate a list.
If you are constructing your own tree representation, you get to choose how it is represented. You might choose to use 'nil' as a terminal symbol, or you might choose 'leaf'. As long as you are consistent, it doesn't matter. - Lyle On Wed, Apr 28, 2010 at 2:54 PM, <[email protected]> wrote: > Here i am again with a new question: > > i'm in trouble about trees. Sometime i see like here > > declare > fun {Size T} > case T > of *nil* then 0 > []tree(_ LT RT) then 1+{Size LT}+{Size RT} > end > end > > is used the NIL. But sometime i see the LEAF in other examples like here > > declare > R=tree(10 uno X1 X2) > X1=tree(5 due X3 X4) > X2=tree(15 tre X5 X6) > X3=tree(1 quattro leaf leaf) > X4=tree(7 cinque leaf leaf) > X5=tree(13 sei leaf leaf) > X6=tree(20 sette leaf leaf) > fun {Lookup X T} > case T > of *leaf* then notfound > [] tree(Y V T1 T2) then > if X==Y then found(V) > elseif X<Y then {Lookup X T1} > elseif X>Y then {Lookup X T2} > end > end > end > {Browse {Lookup 7 R}} > > i don't understand why? When i have to use Nil and when LEAF please? > > ---- > Caselle da 1GB, trasmetti allegati fino a 3GB e in piu' IMAP, POP3 e SMTP > autenticato? GRATIS solo con Email.it<http://www.email.it/cgi-bin/start?sid=3> > > Sponsor: > Apri subito Conto Arancio e ricevi 50 Euro di buoni acquisti da spendere > presso Media World! > Clicca qui <http://adv.email.it/cgi-bin/foclick.cgi?mid=10032&d=20100428> > > > _________________________________________________________________________________ > mozart-users mailing list > [email protected] > http://www.mozart-oz.org/mailman/listinfo/mozart-users >
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