<![CDATA[//************************ IntSLList.java **************************
// singly-linked list class to store integers
public class IntSLList {
private IntNode head, tail;
public IntSLList() {
head = tail = null;
}
public boolean isEmpty() {
return head == null;
}
public void addToHead(int el) {
head = new IntNode(el,head);
if (tail == null)
tail = head;
}
public void addToTail(int el) {
if (!isEmpty()) {
tail.next = new IntNode(el);
tail = tail.next;
}
else head = tail = new IntNode(el);
}
public int deleteFromHead() { // delete the head and return its info;
int el = head.info;
if (head == tail) // if only one node on the list;
head = tail = null;
else head = head.next;
return el;
}
public int deleteFromTail() { // delete the tail and return its info;
int el = tail.info;
if (head == tail) // if only one node in the list;
head = tail = null;
else { // if more than one node in the list,
IntNode tmp; // find the predecessor of tail;
for (tmp = head; tmp.next != tail; tmp = tmp.next);
tail = tmp; // the predecessor of tail becomes tail;
tail.next = null;
}
return el;
}
public void printAll() {
for (IntNode tmp = head; tmp != null; tmp = tmp.next)
System.out.print(tmp.info + " ");
}
public boolean isInList(int el) {
IntNode tmp;
for (tmp = head; tmp != null && tmp.info != el; tmp = tmp.next);
return tmp != null;
}
public void delete(int el) { // delete the node with an element el;
if (!isEmpty())
if (head == tail && el == head.info) // if only one
head = tail = null; // node on the list;
else if (el == head.info) // if more than one node on the list;
head = head.next; // and el is in the head node;
else { // if more than one node in the list
IntNode pred, tmp; // and el is in a non-head node;
for (pred = head, tmp = head.next;
tmp != null && tmp.info != el;
pred = pred.next, tmp = tmp.next);
if (tmp != null) { // if el was found;
pred.next = tmp.next;
if (tmp == tail) // if el is in the last node;
tail = pred;
}
}
}
}
]]>