import java.util.*;

class NodeExample
{
	public static void main(String[] args)
	{
		GraphNode a = new GraphNode(0,0,null);
		GraphNode b = new GraphNode(1,1,a);
		GraphNode c = new GraphNode(2,2,b);
		GraphNode d = new GraphNode(3,3,c);

		ArrayList<GraphNode> nodeList = new ArrayList<GraphNode>();
		nodeList.add(a);
		nodeList.add(b);
		nodeList.add(c);
		nodeList.add(d);

		//This is a java for-each loop.
		//It just steps through the elements in the ArrayList

		Print("First time through");
		for(GraphNode n:nodeList)
		{
			if(n.parent != null)
			{
				Print(n);
			}
		}

		Print("Changing parents");
		for(GraphNode n:nodeList)
		{
			n.SetParent(new GraphNode(10, 10, null));
		}

		Print("Second time through");
		for(GraphNode n:nodeList)
		{
			if(n.parent != null)
			{
				Print(n.parent);
			}
		}
	}


	//This is just a silly class that I like to use cause I'm lazy
	//and I dont want to type System.out.println everytime I want to
	//print something
	public static void Print(Object o)
	{
		System.out.println(o);
	}

}