Blatt 7 Aufgabe 3

public class StapelAlsEVL<T> implements Stapel<T> {

	private class Item {
		Item next;
		T value;
	}

	private Item first;
	private Item last;

	@Override
	public void add(T e) {
		Item item = new Item();
		item.value = e;

        item.next =first;
		first = item;
		}

	@Override
	public T element() {
		if (isEmpty()) {
			throw new java.util.NoSuchElementException();
		}

		return  first.value;
	}

	@Override
	public T remove() {
		if (isEmpty()) {
			throw new java.util.NoSuchElementException();
		}

		T temp = first.value;

		if (first.next == null) {
            first = null;
            last = null;
        } else {
            first = first.next;
        }

		return temp;
	}

	@Override
	public boolean isEmpty() {
		return first == null;
	}

}