BST – Insertion Traversal

/*Copyrights to vsdevelopers.io*/
/*For more programs visit vsdevelopers.io */
/*Program to perform insertion and traversals on Binary Search Tree*/
import java.util.Scanner;

public class VSDBSTcreate {
	static Scanner sc = new Scanner(System.in);

	// Class to hold the structure of node in a tree
	public static class VSDNode {
		int data;// Holds the value of node
		int count;// Holds the count of duplicate nodes
		VSDNode left;// Holds the left pointer of node
		VSDNode right;// Holds the right pointer of node
		// Default constructor

		VSDNode(int data) {
			this.data = data;
			this.count = 0;
			this.left = this.right = null;
		}
	}

	// Root node
	static VSDNode root;

	// Function to insert data into BST
	public static VSDNode VSDinsert(VSDNode root, int data) {
		if (root == null)
			root = new VSDNode(data);
		if (data < root.data)
			root.left = VSDinsert(root.left, data);
		else if (data == root.data)
			root.count += 1;
		else
			root.right = VSDinsert(root.right, data);
		return root;
	}

	// Function to perform inorder traversal
	public static void VSDinorder(VSDNode root) {
		if (root.left != null)
			VSDinorder(root.left);
		System.out.println(root.data);
		if (root.right != null)
			VSDinorder(root.right);
	}

	// Function to perform preorder traversal
	public static void VSDpreorder(VSDNode root) {
		System.out.println(root.data);
		if (root.left != null)
			VSDpreorder(root.left);
		if (root.right != null)
			VSDpreorder(root.right);
	}

	// Function to perform postorder traversal
	public static void VSDpostorder(VSDNode root) {
		if (root.left != null)
			VSDpostorder(root.left);
		if (root.right != null)
			VSDpostorder(root.right);
		System.out.println(root.data);
	}

	// Function to take user data to insert into BST
	public static void VSDdatainsert() {
		System.out.println("Enter data to insert:");
		int data = sc.nextInt();
		root = VSDinsert(root, data);
		System.out.println("Data Inserted");

	}

	// Function to take user input to perform BST operations
	public static void VSDuserInput() {
		System.out.println("Please Enter BST operation from:");
		System.out.println("Insert Inorder Preorder Postorder");
		String choice = sc.next();
		switch (choice) {
		case "Insert":
		case "insert":
			VSDdatainsert();
			break;
		case "Inorder":
		case "inorder":
			if (root == null)
				System.out.println("Tree is empty, Insert elements to traverse");
			else
				VSDinorder(root);
			break;
		case "Preorder":
		case "preorder":
			if (root == null)
				System.out.println("Tree is empty, Insert elements to traverse");
			else
				VSDpreorder(root);
			break;
		case "Postorder":
		case "postorder":
			if (root == null)
				System.out.println("Tree is empty, Insert elements to traverse");
			else
				VSDpostorder(root);
			break;

		}
		VSDuserChoice();
	}

	public static void VSDuserChoice() {
		System.out.println("For performing operations enter y else enter n");
		char ch = sc.next().charAt(0);
		if (ch == 'Y' || ch == 'y')
			VSDuserInput();
		else
			return;
	}

	public static void main(String args[]) {
		VSDuserInput();

	}
}