我坚持如何打印双链表。我必须打印'testListStrings（）'和'testListIntegers（）'
private static void testListIntegers() {
MyLinkedList<Integer> testList = new MyLinkedList<Integer>();
testList.add(new Integer(5));
testList.add(new Integer(4));
testList.add(new Integer(3));
System.out.println(" We have so far inserted " + testList.size() + " elements in the list");
testList.remove(4);
System.out.println(" Now, there is only " + testList.size() + " elements left in the list");
testList.add(1, new Integer(7));
testList.add(2, new Integer(8));
System.out.println(" About to print content of the list");
testList.printList();
}
private static void testListStrings() {
MyLinkedList<String> testList = new MyLinkedList<String>();
testList.add(new String("hello"));
testList.add(new String("this is"));
testList.add(new String("cs3345 project 2"));
System.out.println(" We have so far inserted " + testList.size() + " elements in the list");
testList.remove("this is");
System.out.println(" Now, there is only " + testList.size() + "elements left in the list");
testList.add(1, "a modified version of");
testList.add(2, "cs3345 project 2, call it version 2");
System.out.println(" About to print content of the list");
testList.printList();
}
我看到可能使用toString方法，但我不确定这是否有用。我的代码已经有一个名为printList（）的方法，但它没有任何参数（教授已经为我们编写了代码，我们必须填写代码）。 print方法在链表类中。
更新 -
所以现在在这里，我被困住了，
public void printList() {
MyLinkedList testList = new MyLinkedList();
Node temp = testList.beginMarker;
while(temp != null){
System.out.println(temp.myData);
temp = temp.myHead;
}
}
---我的代码返回null
public class MyLinkedList<AnyType> implements Iterable<AnyType> {
private int theSize;
private Node<AnyType> beginMarker;
private Node<AnyType> endMarker;
public class Node<AnyType> {
public Node(AnyType data, Node<AnyType> head, Node<AnyType> tail) {
myData = data;
myHead = head;
myTail = tail;
}
public AnyType myData;
public Node<AnyType> myHead;
public Node<AnyType> myTail;
}
public MyLinkedList() {
beginMarker = new Node(null, endMarker, null);
endMarker = new Node(null, null, beginMarker);
theSize = 0;
}
public void clear() {
beginMarker.myHead = endMarker;
endMarker.myTail = beginMarker;
}
public int size() {
return theSize;
}
public boolean exist(AnyType newVal){
beginMarker.myHead.myData = newVal;
if(newVal !=null){
return true;
}
return false;
}
public boolean add(AnyType newVal) {
{ add( size(), newVal); return true;}
}
public boolean add(int index, AnyType newVal) {
addBefore( getNode( index, 0, size( ) ), newVal );
return true;
}
public Node<AnyType> get(AnyType nodeData) {
Node<AnyType> node = beginMarker;
while(node != endMarker){
//Means node.data = nodeData
if(node.myData.equals(nodeData)){
return node;
}
}
return null;
}
//Added method
private Node<AnyType> getNode(int index, int lower, int upper){
Node<AnyType> x;
if (index < lower || index > upper)
throw new IndexOutOfBoundsException();
if (index < size() /2){
x = beginMarker.myHead;
for(int i = 0; i <index; i++)
x = x.myHead;
}
else{
x= endMarker;
for(int i = size(); i > index; i--)
x = x.myTail;
}
return x;
}