import java.util.Iterator;


public class GenericList<T> implements Iterator<T>, Iterable<T>{
	
	private GenericNode<T> head;
	private GenericNode<T> iter;
	
	int count;

	public GenericList() {
		head = null;
	}

	public void clear() {
		head = null;
	}
	
	public void insert(T item)
	{
		GenericNode<T> node = new GenericNode<T>(item);
		insert(node);
	}

	public void insert(GenericNode<T> node) {
		node.next = head;

		head = node;
		count ++;
	}

	public void insert(GenericNode<T> n, int index) {

		if (index == 0)
			insert(n);

		GenericNode<T> prev, cur;

		prev = head;
		cur = head.next;

		while (cur != null && index > 1) {
			cur = cur.next;
			prev = prev.next;
			index--;
		}

		prev.next = n;
		n.next = cur;
		
		count ++;
	}

	// Delete the node at the zero-based index.
	public void remove(int index) {
		int cur;
		GenericNode<T> curnode = head;

		for (cur = index; cur > 1; cur--)
			curnode = curnode.next;

		if (curnode == head)
			head = head.next;
		else
			curnode.next = curnode.next.next;
		
		count --;
	}
	
	public void remove()
	{
		remove(0);
	}

	public T getVal(int index) {
		int cur;
		GenericNode<T> curnode = head;

		for (cur = index; cur > 0; cur--)
			curnode = curnode.next;

		// curnode should point to the node whose value we want.
		return curnode.getValue();
	}

	public void print() {
		head.print();
	}
	
	public String toString()
	{
		String res = "<List: " + count + ": ";
		if (head == null) return res + ">";
		
		GenericNode<T> node = head;
		while (node.next != null)
		{
			res += node.getValue() + ", ";
			node = node.next;
		}
		res += node.getValue() + ">";
		return res;
	}
	
	public int length()
	{
		return count;
	}

	//method required by Iterator
	public boolean hasNext() {
		return (iter != null);
	}

	//method required by Iterator
	public T next() {
		// TODO Auto-generated method stub
		T data =  iter.getValue();
		iter = iter.next;
		return data;
	}

	//method required by Iterable
	public Iterator<T> iterator() {
		iter = head;
		return this;
	}
}