import java.util.Scanner; public class BinarySearchTree { /* Class containing left and right child of current node and key value*/ class Node { int key; Node left, right; public Node(int item) { key = item; left = right = null; } } // Root of BST Node root; // Constructor BinarySearchTree() { root = null; } // This method mainly calls insertRec() void insert(int key) { root = insertRec(root, key); } /* A recursive function to insert a new key in BST */ Node insertRec(Node root, int key) { /* If the tree is empty, return a new node */ if (root == null) { root = new Node(key); return root; } /* Otherwise, recur down the tree */ if (key < root.key) root.left = insertRec(root.left, key); else if (key > root.key) root.right = insertRec(root.right, key); /* return the (unchanged) node pointer */ return root; } // This method mainly calls InorderRec() void inorder() { inorderRec(root); } // A utility function to do inorder traversal of BST void inorderRec(Node root) { if (root != null) { inorderRec(root.left); System.out.print(root.key+"\t"); inorderRec(root.right); } } public static void main(String[] args) { BinarySearchTree tree = new BinarySearchTree(); Scanner scan = new Scanner(System.in); int i=1,key; do { System.out.println("Enter your choice"); System.out.println("1.insert\n2.inorder\n3.exit"); i=scan.nextInt(); switch(i) { case 1: key = scan.nextInt(); tree.insert(key); break; case 2: tree.inorder(); System.out.println(); break; case 3: break; default: System.out.println("enter a valid number"); } }while(i!=3); tree.inorder(); } }