String OutOfBound exception

[grisha83]

Hello,
I am getting out of bound error whenever i run the program and trying to add a Node (this would be in my switch). but the error that i am getting is just above my switch statement. Can anyone help me to figure out what it is that i am doing wrong?

import java.util.*;
public class BSTTest {

 
    public static void main(String[] args)
    {
        // Creating Scanner object
        Scanner in = new Scanner(System.in);
        // Local variables
        boolean done  = false;
        char choice;
        String s;
        

        // Constructor call
        BinarySearchTree tree =  new BinarySearchTree();
        tree.DummyNode(29);     // calling on the Dummy Node


        while (!done)   // While statemnt that allows user to keep making selections until requested otherwise
        {
       System.out.println(" Please make a selection:");    // Requesting user to make selection
       s= in.nextLine();        // Reading input from the user as a String
       choice = s.charAt(0);    // Converting String to a Char

       // Swicth statement with selction alternatives
       switch(choice)
        {
            case 'I': 
            case 'i':

                int num;
                System.out.println("Please enter the value of the Node you want to add:");   // Reading user input
                num = in.nextInt();
                tree.insertRoot(num);  // This method is not working well. Only allows to input number once or twice and then something wrong happens
               // tree.search(29);
               // tree.print();
                break;
            case 'D':
            case 'd':
                tree.delete(1);
                System.out.println("test for D");
                break;
            case 'P':
            case 'p':
                tree.print();
                break;
            case 'Q':
            case 'q':
                done = true;
                System.out.println("test for Q");
                System.out.println("Thank you program has exited");
                break;
            default:
               System.out.println("You haven't made right selection. Please re-enter");
               break;
        }
    }
  }
}

[JamesCherrill]

Maybe s contains a zero-length String (""), so there is no char at (0)

[BestJewSinceJC]

Yes but wouldn't grisha have realized that? The only way to get a 0 length String there is to just hit enter....

[grisha83]

hehe, i did hit enter. I am not sure if it will help you but the problem disappears if i remove reading of the user input in Switch in case 'I' and place it in my method. In fact, this is where I intended to have it in the beginning (i thought this would be cleaner). Well then i had another error popping up which only allowed me to enter up to 2 Nodes max but at least the program worked.

[BestJewSinceJC]

If your insertRoot method isn't working, and you want help with it, you'll have to post all the relevant code

[grisha83]

Well its working now after I moved the prompt from the user to input Node values to my main. But anyway, here is the entire program:
// Node

public class Node {
    public int data;
    public Node left;
    public Node right;

    public Node()   // No argumennt constructor initializing the variables
    {
        data = 0;   // Node value
        left = null; // Left Node
        right = null; // Right Node
    }
    public Node(int val)   // One argumennt constructor initializing the variables
    {
     data = val; // Node value
     left = null;  // Right Node
     right = null; // Left Node
    }

// Class BinarySearchTree

public class BinarySearchTree {

    private Node root;

    public BinarySearchTree() {
        root = null;
    }

    public Node DummyNode(int val) // Dummy Node with initial value of any number
    {
        if (root == null) {
            root = new Node(val);
        } else {
            insertRoot(val);
        }

        return root;
    }

    public int insertRoot(int num) // Insertion of a new Node with value
    {


        if (num > root.data) // When new Node is smaller then root
        {
            if (root.right == null) {
                root.right = new Node(num);

            } else {
                root = root.right;
                insertRoot(num);
            }
        }
        if (num < root.data) // When new Node is larger then root
        {
            if (root.left == null) {
                root.left = new Node(num);
            } else {
                root = root.left;
                insertRoot(num);
            }
        }
        return num;
    }

    public void print() // Printing Nodes in-order
    {
        System.out.print("Nodes organized in 'in-order' are: ");
        moveToNext(root);
    }

    public void moveToNext(Node root) // Traversing in-order
    {
        if (root == null) {
            return;
        }

        if (root.left != null) {
            moveToNext(root.left);
        }

        System.out.print(root.data + "    ");
        if (root.right != null) {
            moveToNext(root.right);
        }
    }

    public void delete(int value) // To delete the Node
    {
        Node parent = null;
        //  target value equals to the root value
        if (value == root.data) {
            Node cur = root;
            // Right side of the tree
            cur = cur.right;

            // If there are a children
            while (cur.left != null) {
                parent = cur;
                cur = cur.left;
            }
            // If there is a child on the right
            cur.left = root.left;
            cur.right = root.right;
            parent.left = null;
            root = cur;
        }
    }
}

// Main

import java.util.*;
public class BSTTest {

 
    public static void main(String[] args)
    {
        // Creating Scanner object
        Scanner in = new Scanner(System.in);
        // Local variables
        boolean done  = false;
        char choice;
        String s;
        

        // Constructor call
        BinarySearchTree tree =  new BinarySearchTree();
        tree.DummyNode(29);     // calling on the Dummy Node


        while (!done)   // While statemnt that allows user to keep making selections until requested otherwise
        {
       System.out.println(" Please make a selection:");    // Requesting user to make selection
       s = in.nextLine();        // Reading input from the user as a String
       choice = s.charAt(0);    // Converting String to a Char
     
       // Swicth statement with selction alternatives
       switch(choice)
        {
            case 'I': 
            case 'i':

                int num;
                System.out.println("Please enter the value of the Node you want to add:");   // Reading user input
                num = in.nextInt();
                tree.insertRoot(num);  // This method is not working well. Only allows to input number once or twice and then something wrong happens
               // tree.search(29);
               
                break;
            case 'D':
            case 'd':
                tree.delete(1);
                System.out.println("test for D");
                break;
            case 'P':
            case 'p':
                tree.print();
                break;
            case 'Q':
            case 'q':
                done = true;
                System.out.println("test for Q");
                System.out.println("Thank you program has exited");
                break;
            default:
               System.out.println("You haven't made right selection. Please re-enter");
               break;
        }
    }
  }
}