Algorithmen und Datenstrukturen Vorlesungsskript WS/SS 99-00

}
public Object dequeue()
throws QueueException {
Object elem;
if (isEmpty())
throw new QueueException("Schlange ist leer");
elem = head.getElement();
head = head.getNext(); size--;
return elem;
}
public Object front()
throws QueueException {
if (isEmpty())
throw new QueueException("Schlange ist leer");
return head.getElement();
}
public void enqueue(Object element){
Node n = new Node(element,null);
Node x = head;
if (isEmpty()){ head = n;}
else {
while ( ! (x.getNext() == null) )
x = x.getNext();
x.setNext(n);
};
size++;
}
ListQueue.java
/* Queue "uber Liste mit zwei Ankern */
class ListQueue implements Queue {
private Node head;
private Node tail;
private int size;
public ListQueue () {
head = null; tail = null; size = 0;
}
public int size(){
return size;
}
public boolean isEmpty() {
return (size == 0);
}
public Object dequeue()
throws QueueException {
Object elem;
if (isEmpty())
throw new QueueException("Schlange ist leer");
elem = head.getElement();
head = head.getNext();
size--;
if (isEmpty()) { tail = null; };
return elem;
}
public Object front()
throws QueueException {
if (isEmpty())
throw new QueueException("Schlange ist leer");
return head.getElement();
}
8.2. Verkettete Listen
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