[1511] in java-interest
Re: dynamic lists
daemon@ATHENA.MIT.EDU (Jason Weiler)
Wed Sep 6 16:27:25 1995
Date: Wed, 6 Sep 1995 10:49:35 -0700
From: weilerj@std.teradyne.com (Jason Weiler)
To: java-interest@java.Eng.Sun.COM
> I am trying to implement something on the level of a linked list of
> indeterminate length in java. From reading the docs and hearing a few
> talks, it seems that the Array is the data structure for this.
> But doesn't the array need a size at time of creation?
> Is there a way to "grow" an array (sort of a realloc)?
>
> I want to go along collecting Strings and adding them to a list of some
> kind: I won't know how many elements will be in the list till I'm done
> collecting.
>
> Once I figure this out, I'll be passing the contents of this list back
> from a native method that does a database lookup to retrieve the
> data, then turn it into Strings: java will then do the
> display stuff.
>
Just cuz Java can't do pointers, doesn't mean you can't do linked
lists the old fashioned way. (Now if I'm wrong here, someone please
snap me back in line. :-)
I wrote this cheesy little class on a lark to see if it could be done,
which it obviously could.
********************* start code *********************
import java.lang.*;
class ll {
static private ll head=null;
static private ll point=null;
private int value;
private ll next=null;
protected ll (int newval) {
value = newval;
next = null;
}
public ll () {
value = 0;
next = null;
}
public void addlink(int newval) {
if (head == null) {
head = new ll(newval);
}
else {
point = head;
while (point.next != null)
point = point.next;
point.next = new ll(newval);
}
}
public void show() {
if (head==null) {
System.out.println("Sorry, head is null");
}
else {
point = head;
while (point != null) {
System.out.println(point.value);
point = point.next;
}
}
}
public static void main (String args[]) {
ll top = new ll();
top.addlink(0);
top.addlink(1);
top.addlink(5);
top.addlink(3);
top.show();
top.show();
}
}
********************* stop code *********************
Well, that should just about do it. I know it's not commented, but
as I said, it was a test program to begin with, and it's very simple.
If anyone needs help with it, please drop me a line.
-Jason W.
<weilerj@std.teradyne.com>
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