Class Code 10/13/17

IteratorEx.java

import java.util.ArrayList;
import java.util.Iterator;

public class IteratorEx {
    public static void main(String[] args){
        ArrayList<String> ships = new ArrayList<>();
        ships.add("Enterprise");
        ships.add("Voyager");
        ships.add("Defiant");

        Iterator<String> it = ships.iterator();

        while(it.hasNext()){
            System.out.println(it.next());
        }

        for (String s : ships){
            System.out.println(s);
        }
    }
}

import java.util.ArrayList;

import java.util.Iterator;

public class IteratorEx {

public static void main(String[] args){

ArrayList<String> ships = new ArrayList<>();

ships.add("Enterprise");

ships.add("Voyager");

ships.add("Defiant");

Iterator<String> it = ships.iterator();

while(it.hasNext()){

System.out.println(it.next());

}

for (String s : ships){

System.out.println(s);

}

LinkedList.java

import java.util.Iterator;

public class LinkedList<T> implements Iterable<T> {

    public class LLIterator<U> implements Iterator<U>{
        LinkedList<U>.Node<U> current;
        LinkedList<U> ll;

        public LLIterator(LinkedList<U> ll){
            current = null;
            this.ll = ll;
        }

        public boolean hasNext(){
            if (current == null) return !ll.isEmpty();
            return current.next != null;
        }

        public U next(){
            if (current == null) current = ll.head;
            else current = current.next;
            return current.data;
        }
    }
    
    private class Node<T> {
        T data;
        Node<T> next;

        public Node(T data){
            this.data = data;
        }

        public Node(T data, Node<T> next){
            this(data);
            this.next = next;
        }

        public String toString(){
            return "" + data;
        }
    }

    private Node<T> head, tail;
    private int count;

    public LinkedList(){
        head = tail = null;
        count = 0;
    }

    public LinkedList(T d){
        head = tail = new Node<T>(d);
        count = 1;
    }

    public int length() {
        return count;
    }

    public boolean isEmpty(){
        return head == null;
    }

    public void append(T d){
        if (isEmpty()) 
            head = tail = new Node<T>(d);
        else 
            tail = tail.next = new Node<T>(d);
        count++;
    }

    public void prepend(T d){
        if (isEmpty()) {
            head = tail = new Node<T>(d);
        } else {
            head = new Node<T>(d, head);
        }
        count++;
    }

    public T getFirst() {
        return head.data;
    }

    public Iterator<T> iterator(){
        return new LLIterator<T>(this);
    }

    public String toString(){
        String retVal = "Linked List with " + count + " nodes: ";

        for (Node<T> temp = head ; temp != null ; temp = temp.next){
            retVal += temp + " ";
        }

        return retVal;
    }

    /* You implement (without using the Iterator!): 
     * public void insert(T data, int index)
     * public boolean exists(T data)
     * public boolean remove(T data)
     * public T get(int index)
     */
}

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import java.util.Iterator;

public class LinkedList<T> implements Iterable<T> {

public class LLIterator implements Iterator{

LinkedList.Node current;

LinkedList ll;

public LLIterator(LinkedList ll){

current = null;

this.ll = ll;

}

public boolean hasNext(){

if (current == null) return !ll.isEmpty();

return current.next != null;

}

public U next(){

if (current == null) current = ll.head;

else current = current.next;

return current.data;

}

private class Node<T> {

T data;

Node<T> next;

public Node(T data){

this.data = data;

}

public Node(T data, Node<T> next){

this(data);

this.next = next;

}

public String toString(){

return "" + data;

}

private Node<T> head, tail;

private int count;

public LinkedList(){

head = tail = null;

count = 0;

}

public LinkedList(T d){

head = tail = new Node<T>(d);

count = 1;

}

public int length() {

return count;

}

public boolean isEmpty(){

return head == null;

}

public void append(T d){

if (isEmpty())

head = tail = new Node<T>(d);

else

tail = tail.next = new Node<T>(d);

count++;

}

public void prepend(T d){

if (isEmpty()) {

head = tail = new Node<T>(d);

} else {

head = new Node<T>(d, head);

}

count++;

}

public T getFirst() {

return head.data;

}

public Iterator<T> iterator(){

return new LLIterator<T>(this);

}

public String toString(){

String retVal = "Linked List with " + count + " nodes: ";

for (Node<T> temp = head ; temp != null ; temp = temp.next){

retVal += temp + " ";

}

return retVal;

}

/* You implement (without using the Iterator!):

* public void insert(T data, int index)

* public boolean exists(T data)

* public boolean remove(T data)

* public T get(int index)

}

Main.java

public class Main {
  public static void main(String[] a) {
    LinkedList<String> ll = new LinkedList<>("abc");
    ll.prepend("def");
    ll.append("hij");
    System.out.println(ll.toString());

    //Use the Iterator to concatenate all strings in the list.
    String ret = "";
    for (Iterator<String> it = ll.iterator(); it.hasNext() ; ){
        ret += it.next();
    }
    System.out.println(ret);

    ret = "";
    for(String s : ll){
        ret += s;
    }
    System.out.println(ret);
  }
}

public class Main {

public static void main(String[] a) {

LinkedList<String> ll = new LinkedList<>("abc");

ll.prepend("def");

ll.append("hij");

System.out.println(ll.toString());

//Use the Iterator to concatenate all strings in the list.

String ret = "";

for (Iterator<String> it = ll.iterator(); it.hasNext() ; ){

ret += it.next();

}

System.out.println(ret);

ret = "";

for(String s : ll){

ret += s;

}

System.out.println(ret);

}

Hi There!

IteratorEx.java

LinkedList.java

Main.java