Re: Problems instantiating a Vector<Vector<Integer>>

"hiwa" <>
31 Oct 2006 17:38:09 -0800
<> wrote:


i'm having some problems with instantiating a vector of vectors of

From the debugger i can see that all of the vector elements (which are

vectors) are null. But i am unable to point them to a *new* vector
because i can't iterate them.

// i can create the "main" vector, but i still need to instantiate all
100 Vectors of Integers
Vector<Vector<Integer>> skips = new Vector<Vector<Integer>>(100);

// the problem with this is that hasMoreElements returns false
Enumeration it = skips.elements();
if (it.hasMoreElements())
  elem = (Vector<Integer>)it.nextElement();

// also suffers from the same problem... it says that it has no
ListIterator<Vector<Integer>> it = skips.listIterator();
if (it.hasNext())
  elem = new Vector<Integer>();

How do i fix this?
Thanks in advance!

If you haven't instantiated it, it should be null.
It is only natural.
Try this:
import java.util.*;

public class VecVec{

  public static void main(String[] args){
    Vector<Vector<Integer>> vvi;
    Vector<Integer> elem = null;

    vvi = new Vector<Vector<Integer>>();
    for (int i = 0; i < 100; ++i){
      vvi.add(new Vector<Integer>());

    Enumeration<Vector<Integer>> it = vvi.elements();
    if (it.hasMoreElements()){
      elem = (Vector<Integer>)it.nextElement();
    System.out.println(elem != null);

    elem = null;
    ListIterator<Vector<Integer>> lit = vvi.listIterator();
    if (lit.hasNext()){
      elem = (Vector<Integer>);
    System.out.println(elem != null);

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