Implenting Iterator interface in a linked list class

Question

  public boolean hasNext() {
          // TODO Auto-generated method stub
          return current != null;
      }


      public T next() throws NoSuchElementException {

          if (!hasNext())
              throw new NoSuchElementException();
          else  
              prev = current;
          current = current.next;


          return (T) prev.data;
      }

  //This is my linked list
 f.add(132);
  f.add(133);

//while loop I am using in regular main method to test
 while(f.iterator().hasNext()){
System.out.println(f.iterator().next());
 }

For some reason I just get an infinite loop here and I am not sure why. I ran this in my main method and it just kept printing 132, I am not sure what's wrong.

Can you also add your code for Linked List and how you are creating iterator to get more clarity? — chauhraj
– chauhraj, Commented Mar 13, 2014 at 4:36

Hirak · Accepted Answer · 2014-03-13 04:32:49Z

1

Get the iterator out of the loop. You are getting a new iterator every time the loop completes one circle. Thus just the first element is printed again and again.

answered Mar 13, 2014 at 4:32

Hirak

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Comments

Banukobhan Nagendram · Accepted Answer · 2014-03-14 01:47:13Z

0

Since the same element print again and again, there are 2 possibility could be happen.

The iterator is not moving and pointed to same element, even after you call next.
The linked-list is a circular one, iterator is automatically moving without call next. So iterator move to next Node (value = 133) and then calling next will move it to same element, since it is circular one.

I hope the problem is with the linked-list code. So give the linked-list code. It will help to find out the bug.

answered Mar 14, 2014 at 1:47

Banukobhan Nagendram

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