public class TreePrint2 {
	public static void main(String[] args) {
		Node root =
			new Node(15,
				new Node(12,
					new Node(6),
					new Node(14)
				),
				new Node(40,
					new Node(25),
					new Node(80)
				)
			);

		//Print the tree.
		print(root, 0);
		System.exit(0);
	}

	//Print the tree rooted at node.

	private static void print(Node node, int indent) {
		if (node != null) {
			print(node.left, indent + 1);
			System.out.println("   ".repeat(indent) + node.value);
			print(node.right, indent + 1);
		}
	}
}


/*
Try the other orders:

			//Swap left and right.
			print(node.right, indent + 1);
			System.out.println("   ".repeat(indent) + node.value);
			print(node.left, indent + 1);

			//Print the root first, followed by the left and right asubtrees.
			System.out.println("   ".repeat(indent) + node.value);
			print(node.left, indent + 1);
			print(node.right, indent + 1);
*/



class Node {
	int value;
	Node left;
	Node right;

	Node(int value, Node left, Node right) {
		this.value = value;
		this.left = left;
		this.right = right;
	}

	Node(int value) {
		this.value = value;
		//this.left and this.right implicitly initialized to null
	}
};