package list;
public class LinkedList implements List {
//Datenfeld
private Element item;
//Zeigerfeld
private LinkedList next;
//Konstruktor, erzeugt leere Liste
public LinkedList() {
item = null;
next = null;
}
//Selektoren
public Object getItem() {
return item;
}
public LinkedList next() {
return next;
}
//ist die Liste leer?
public boolean isEmpty() {
return next == null;
}
public Object firstElement() {
if (isEmpty())
return null;
else
return next.item;
}
public int length() {
if (isEmpty())
return 0;
else
return 1 + next.length();
}
//fügt x am Kopf ein
public LinkedList insert(Element x) {
LinkedList l = new LinkedList();
l.item = x;
l.next = next;
next = l;
return this;
}
//hängt das x ans Ende der Liste und liefert Teilliste
public LinkedList append (Element x) {
if (isEmpty())
return insert(x);
else
return next.append(x);
}
//liefert Null, falls x nicht in Liste
//sonst Teilliste
private LinkedList find(Element x) {
if (isEmpty())
return null;
else
if (firstElement().equals(x))
return this;
else
return next.find(x);
}
//entfertn erstes x der Liste
public LinkedList delete(Element x) {
LinkedList l = find(x);
if (l != null)
return l.next = l.next.next;
else
return this;
}
//entfernt das erste Element der Liste
public LinkedList delete() {
if (!isEmpty())
next = next.next;
return this;
}
public boolean isInList(Element x) {
return(find(x) != null);
}
public String toString() {
return (next == null ? " |--" : " --> " + next.item + next);
}
static void println(Element x) {
System.out.println(x.toString());
}
public LinkedList add(Element x, int n) {
return null;
}
public LinkedList remove(int n) {
return null;
}
public Element get(int n) {
return null;
}
public int firstIndexOf(Element x) {
return 1;
}
public int lastIndexOf(Element x) {
return 1;
}
LinkedList l1 = new LinkedList();
l1.insert("AA");
}
在最后一行(l1.insert("AA");我得到了错误
Type Syntax error on token(s), misplaced construct(s).
需要帮忙。找不到问题。