public void print(int index)
	{
	    System.out.println("\r" + tree.elementAt(index).item
	         + "(" + tree.elementAt(index).chance_weight
	         + "/" + tree.elementAt(index).family_weight + ")");

	    if(2*index+1 < tree.size()){ // has son
	        System.out.println("\tson[" + (2*index+1) + "]:" + tree.elementAt(2*index+1).item);
	    }
	    if(2*(index+1) < tree.size()) { // also has daughter
	        System.out.println("\tdaughter[" + (2*(index+1)) + "]:" + tree.elementAt(2*(index+1)).item);
	    }
	};