import java.util.Iterator;

class FIFOListe<T> implements Iterable<T> {

    private Node start;
    private Node slutt;
  
    private class Node {
        Node neste;
        T verdi;
  
        Node(T verdi) {
            this.verdi = verdi;
        }
    }
  
    public int storrelse() {
        int teller = 0;
        for (Node tmp = start; tmp != null; tmp = tmp.neste) {
            teller++;
        }
        return teller;
    }
  
    public boolean erTom() {
        return start == null;
    }
  
    public void leggTil(T t) {
        Node nyNode = new Node(t);
        if (erTom()) {
            start = nyNode;
            slutt = nyNode;
        } else {
            slutt.neste = nyNode;
            slutt = nyNode;
        }
    }
  
    public void fjernAlt() {
        start = null;
        slutt = null;
    }
  
    public T pop() {
        Node tmp = start;
        start = start.neste;
        return tmp.verdi;
    }
  
    public void skrivUtListe() {
        Node tmp = start;
        System.out.println("[");
        while (tmp != null) {
            System.out.println("\t" + tmp.verdi);
            tmp = tmp.neste;
        }
        System.out.println("]");
    }
  
    public Iterator<T> iterator() { 
        return new FIFOIterator();
    }

    private class FIFOIterator implements Iterator<T> {

        Node nextInLine = start;

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

        @Override
        public T next() {
            Node tmp = nextInLine;
            nextInLine = nextInLine.neste;
            return tmp.verdi;
        }
    }
}