Trouble adding item to a java linked list

Question

The last part of this program should be adding the pickles item between the lettuce and chicken item, but whenever I run it it adds it to the end of the list. I have no idea why. Is this a problem with the way I'm outputting it? I honestly have no idea why this is happening. Please help!

public class LinkedListDemo 
{
  public static void main(String[] args) 
  {

List<String> myLinkedList = new LinkedList<String>();

String strOutput="";

myLinkedList.add("Bread1");
myLinkedList.add("mustard");
myLinkedList.add("lettuce");
myLinkedList.add("chicken");
myLinkedList.add("tomato");
myLinkedList.add("Bread2");

ListIterator<String> lit = myLinkedList.listIterator();
while(lit.hasNext()) 
{
  strOutput +=(lit.next() + ", ");
}
strOutput +=("end...\n");    


while(lit.hasPrevious()) 
{
  strOutput +=(lit.previous() + ", ");
}
strOutput +=("end...\n");


lit.next();
lit.next();
lit.next();

myLinkedList.add("pickles");

ListIterator<String> lit2 = myLinkedList.listIterator();

while(lit2.hasNext()) 
{
  strOutput +=(lit2.next() + ", ");
}
strOutput +=("end...\n");    

javax.swing.JOptionPane.showMessageDialog(null, strOutput);
System.exit(0);
  }

}

Maarten Bodewes · Accepted Answer · 2015-10-22 23:18:43Z

2

Your list is separate from the iterator in the sense that the state of the iterator isn't reflected in the list itself. To add something using the iterator, use the add method of the iterator.

answered Oct 22, 2015 at 23:18

Maarten Bodewes

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1 Comment

Runic Over a year ago

Ah, that is the source of my confusion! Thank you very much!

pgiitu · Accepted Answer · 2015-10-22 23:18:50Z

0

myLinkedList.add("pickles"); will always add it in the end. It doesnot matter where the iterator is. They are both independent.

You should use: myLinedList.add(3,"pickles") to add it between "lettuce" and "chicken"

or

You can use the iterators add method to add it where ever you want. http://docs.oracle.com/javase/7/docs/api/java/util/ListIterator.html#add(E)

answered Oct 22, 2015 at 23:18

pgiitu

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1 Comment

Runic Over a year ago

That is also a good way to do it! Thanks to all of you for these very good responses! The rest of the program should be a snap.

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