-JAVA- provide a test class that do the required -you may add methods you need in the SLL- //************************** SLL.java ********************************* // a generic singly linked list class public class SLL{ private class SLLNode { private T info; private SLLNode next; public SLLNode() { this(null,null); } public SLLNode(T el) { this(el,null); } public SLLNode(T el, SLLNode ptr) { info = el; next = ptr; } } protected SLLNode head, tail; public SLL() { head = tail = null; } public boolean isEmpty() { return head == null; } public void addToHead(T el) { head = new SLLNode(el,head); if (tail == null) tail = head; } public void addToTail(T el) { if (!isEmpty()) { tail.next = new SLLNode(el); tail = tail.next; } else head = tail = new SLLNode(el); } public T deleteFromHead() { // delete the head and return its info; if (isEmpty()) return null; T el = head.info; if (head == tail) // if only one node on the list; head = tail = null; else head = head.next; return el; } public T deleteFromTail() { // delete the tail and return its info; if (isEmpty()) return null; T 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, SLLNode 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 delete(T el) { // delete the node with an element el; if (!isEmpty()) if (head == tail && el.equals(head.info)) // if only one head = tail = null; // node on the list; else if (el.equals(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 SLLNode pred, tmp;// and el is in a nonhead node; for (pred = head, tmp = head.next; tmp != null && !tmp.info.equals(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; } } } @Override public String toString() { if(head == null) return "[ ]"; String str = "[ "; SLLNode tmp = head; while(tmp != null){ str += tmp.info + " "; tmp = tmp.next; } return str+"]"; } public boolean contains(T el) { if(head == null) return false; SLLNode tmp = head; while(tmp != null){ if(tmp.info.equals(el)) return true; tmp = tmp.next; } return false; } public int size(){ if(head == null) return 0; int count = 0; SLLNode p = head; while(p != null) { count++; p = p.next; } return count; } // // Please write the methods of Task02 here: // public void insertBefore(int index, T newElem) throws Exception { //throws exception if the list is empty if(isEmpty()){ throw new Exception("list is empty"); } //inserts if(index < size()){ if (index == 0){ SLLNode newnode = new SLLNode<>(newElem, head); head = newnode; } else{ SLLNode temp = head; SLLNode newnode = new SLLNode<>(newElem, null); for (int i = 0; i < index - 1; i++) { temp = temp.next; } newnode.next = .

1. -JAVA-
provide a test class that do the required
-you may add methods you need in the SLL-
//************************** SLL.java *********************************
// a generic singly linked list class
public class SLL{
private class SLLNode {
private T info;
private SLLNode next;
public SLLNode() {
this(null,null);
}
public SLLNode(T el) {
this(el,null);
}
public SLLNode(T el, SLLNode ptr) {
info = el; next = ptr;
}
}
protected SLLNode head, tail;
public SLL() {
head = tail = null;
}
public boolean isEmpty() {
return head == null;
}
public void addToHead(T el) {
head = new SLLNode(el,head);
if (tail == null)
tail = head;
}
public void addToTail(T el) {
if (!isEmpty()) {
tail.next = new SLLNode(el);
tail = tail.next;

2. }
else head = tail = new SLLNode(el);
}
public T deleteFromHead() { // delete the head and return its info;
if (isEmpty())
return null;
T el = head.info;
if (head == tail) // if only one node on the list;
head = tail = null;
else head = head.next;
return el;
}
public T deleteFromTail() { // delete the tail and return its info;
if (isEmpty())
return null;
T 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,
SLLNode 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 delete(T el) { // delete the node with an element el;
if (!isEmpty())
if (head == tail && el.equals(head.info)) // if only one
head = tail = null; // node on the list;
else if (el.equals(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
SLLNode pred, tmp;// and el is in a nonhead node;
for (pred = head, tmp = head.next;
tmp != null && !tmp.info.equals(el);

3. 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;
}
}
}
@Override
public String toString() {
if(head == null)
return "[ ]";
String str = "[ ";
SLLNode tmp = head;
while(tmp != null){
str += tmp.info + " ";
tmp = tmp.next;
}
return str+"]";
}
public boolean contains(T el) {
if(head == null)
return false;
SLLNode tmp = head;
while(tmp != null){
if(tmp.info.equals(el))
return true;
tmp = tmp.next;
}
return false;
}
public int size(){
if(head == null)

4. return 0;
int count = 0;
SLLNode p = head;
while(p != null) {
count++;
p = p.next;
}
return count;
}
//
// Please write the methods of Task02 here:
//
public void insertBefore(int index, T newElem) throws Exception {
//throws exception if the list is empty
if(isEmpty()){
throw new Exception("list is empty");
}
//inserts
if(index < size()){
if (index == 0){
SLLNode newnode = new SLLNode<>(newElem, head);
head = newnode;
}
else{
SLLNode temp = head;
SLLNode newnode = new SLLNode<>(newElem, null);
for (int i = 0; i < index - 1; i++) {
temp = temp.next;
}
newnode.next = temp.next;
temp.next = newnode;
}

5. }
//throws exception for invalid index
else {
throw new Exception("index is not valid");
}
}
public T delete(int index) throws Exception{
//throws exception if the list is empty
if (isEmpty()) {
throw new Exception("list is empty");
}
//removes
if (index < size()) {
if (index == 0) {
return deleteFromHead();
}
else if (index == size() - 1) {
return deleteFromTail();
}
SLLNode temp = head;
for (int i = 0; i < index - 1; i++) {
temp = temp.next;
}
T elm = temp.next.info;
temp.next = temp.next.next;
return elm;
}
//invalid index
throw new Exception("index is not valid");
}
public void insertAfterSecondOccurrence(T e1, T e2) throws Exception {

6. //throws exception if the list is empty
if (isEmpty()) {
throw new Exception("list is empty");
}
//inserts
int pos = -1;
int counter = 0;
SLLNode temp = head;
for (int i = 0; i < size(); i++) {
if (temp.info == e2) {
counter++;
}
if (counter == 2) {
pos = i;
break;
}
temp = temp.next;
}
if (pos != -1) {
if (pos + 1 == size()) {
addToTail(e1);
} else {
insertBefore(pos + 1, e1);
}
}
//the list has no second occurrence of e2
if (pos == -1){
throw new Exception("list has no second occurrence of " + e2);
}
}
} Part I: Programming (50 points) Use the singly linked list class introduced in the lab to
implement integers of unlimited size. Each node of the list should store one digit of the integer.
You are to implement the addition, subtraction and multiplication operations. Please note that
any additional data structure to be used in solving this problem has to be taken from the ones
introduced in the ICS 202 lab. In addition, provide a test class that will do the following: It will

7. keep asking the user to enter two integers, choose one of the operations (addition, subtraction,
multiplication) and then display the result. The program will stop upon entering the "#"
character (without the double quotes).