// An IntTree object represents an entire binary tree of ints.
public class IntTree {
	IntTreeNode overallRoot;

	// Constructs an empty binary tree
	public IntTree() {
		overallRoot = null;
	}

	// Constructs a binary tree with the given node as its root.
	public IntTree(IntTreeNode overallRoot) {
		this.overallRoot = overallRoot;
	}

	// Prints a pre-order traversal of this tree.
	public void printPreOrder() {
		printPreOrder(overallRoot);
		System.out.println();
	}

	// Prints a pre-order traversal of the tree starting at the specified root
	private void printPreOrder(IntTreeNode root) {
		// implicit base case: do nothing if we reach a null root
		if (root != null) {
			System.out.print(root.data + " ");
			printPreOrder(root.left);
			printPreOrder(root.right);
		}
	}

	// Prints an in-order traversal of this tree.
	public void printInOrder() {
		printInOrder(overallRoot);
		System.out.println();
	}

	// Prints an in-order traversal of the tree starting at the specified root
	private void printInOrder(IntTreeNode root) {
		if (root != null) {
			printInOrder(root.left);
			System.out.print(root.data + " ");
			printInOrder(root.right);
		}
	}

	// Prints a post-order traversal of this tree.
	public void printPostOrder() {
		printPostOrder(overallRoot);
		System.out.println();
	}

	// Prints a post-order traversal of the tree starting at the specified root
	private void printPostOrder(IntTreeNode root) {
		if (root != null) {
			printPostOrder(root.left);
			printPostOrder(root.right);
			System.out.print(root.data + " ");
		}
	}
}