import java.util.Iterator;

public class FIFOListe<T> implements Iterable<T>{

	private Node start;
	private Node slutt;

	private class Node {
        Node neste;
        T data;

        Node(T data){
            this.data = data;
        }
    }

	public int storrelse() {
        int teller = 0;
        Node p = start;
        while (p != null){
            teller++;
            p = p.neste;
        }
        return teller;
    }

	public boolean erTom() {
        return start == null;
    }

	public void leggTil(T d) {
        Node nyNode = new Node(d);
        if (erTom()){
            start = nyNode;
        }
        else {
            slutt.neste = nyNode;
        }
        slutt = nyNode;
    }

	public void fjernAlt() {
        start = null;
        slutt = null;
    }

	public T pop(){ // fjerne element -> første
        Node returNode = start;
        start = start.neste;
        return returNode.data;
    }

	public void skrivUtListe() {
        Node p = start;
        while(p != null){
            System.out.println(p.data);
            p = p.neste;
        }
    }

    @Override       
    public Iterator<T> iterator() {
        return new FIFOIterator();
    } 

    private class FIFOIterator implements Iterator<T> {

       Node denne = start;

       @Override
       public boolean hasNext() {
           return denne != null;
       }

       @Override
       public T next() {
           if (denne == null) throw new NoSuchElementException("next");
           Node p = denne;
           denne = denne.neste;
           return p.data;
       }
  }
}