This is an implementation of the binary search tree. Reference - Introduction to Algorithms

BinarySearchTree.java

public class BinarySearchTree {
	void in_order_tree_walk(Node x) {
		in_order_tree_walk(x.left);
		System.out.println(x.key);
		in_order_tree_walk(x.right);
	}

	void insert(Node T, Node x) {
		Node y = T;
		while (y != null) {
			if (y.key < x.key) {
				if (y.right == null)
					y.right = x;
				else
					y = y.right;
			} else {
				if (y.left == null)
					y.left = x;
				else
					y = y.left;
			}
		}

	}

	Node minimum(Node x) {
		while (x.left != null) {
			x = x.left;
		}
		return x;
	}

	Node maximum(Node x) {
		while (x.right != null) {
			x = x.right;
		}
		return x;
	}

	Node treeSearch(Node x, int key) {
		if (x == null || x.key == key) {
			return x;
		}
		if (x.key < key) {
			return treeSearch(x.left, key);
		} else {
			return treeSearch(x.right, key);
		}
	}

	Node itereativeTreeSearch(Node x, int key) {
		while (x != null && x.key != key) {
			if (x.key < key)
				x = x.right;
			else
				x = x.left;
		}
		return x;
	}
}

class Node {
	Node left;
	Node right;
	int key;

	Node(int key) {
		this.key = key;
	}
}