[1735] in java-interest
Re: pointer in java
daemon@ATHENA.MIT.EDU (Simon Spero)
Fri Sep 15 12:22:02 1995
Date: Thu, 14 Sep 1995 12:53:07 -0700 (PDT)
From: Simon Spero <ses@tipper.oit.unc.edu>
To: Larry Liang <lliang@bellcore.com>
Cc: java-interest@java.Eng.Sun.COM
In-Reply-To: <199509131450.KAA00581@scherzo.bellcore.com>
On Wed, 13 Sep 1995, Larry Liang wrote:
> Since there is no pointer in java, how do I create a linked list of a
> tree. The handle is more like a reference in C++ which does not seem
> to be able to change the object it's referring to.
Wrong(ish) - just about everything is a pointer in java. I posted an
example of a doubly linked list a week or so back, but here's a little
example for a silly linked list implementation. Static functions are used
to give the usual non-oo interface.
interface closure {
public object funcall(object o);
};
class list {
public Object car;
public list cdr;
public list(Object o , list l) {
_car = o ; _cdr = l
}
public static list cons(Object o, list l) {
return new list(o,l);
}
public static list append(list a,list b) {
if(a == nil) {
return b;
} else {
return cons(a.car,append(a.cdr,b));
}
}
public static list reverse(list a) {
return reverse_2(a,nil);
}
public static list reverse_2(list a, list acc) {
if(a == nil) {
return acc;
} else {
return reverse_2(a.cdr,cons(a.car,acc));
}
}
public static list map(closure f, list a) {
if(a == nil) {
return nil;
} else {
return cons(f.funcall(a.car),a.cdr);
}
}
};
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