In-order traversal BST

Question

I want my output to come out as follows:

(E: HAR@litfried L: R: (E: HAR@tika L: (E: HAR@LynConway L: R: ) R: ) ). I've tried everything possible but I keep getting this instead. (E: HAR@litfried L: R: (E: HAR@tika L: R: (E: HAR@LynConway L: R: ) ) ).

Here is my code:

public class BST {
    private BSTNode root;

    public BST(){
        root = null;
    }

    public void insertColleague(Colleague c) {
        BSTNode node = new BSTNode(c);
        if (root == null){
            root = node;
        }else {
            insertColleague(root, node);
        }

    }

    private void insertColleague(BSTNode currNode, BSTNode node) {
        if(currNode.getC().getUserName().compareTo(root.getC().getUserName())<0){
            if (currNode.getL() == null){
                currNode.setL(node);
            } else {
                insertColleague(currNode.getL(), node);
            }
        } else{
            if (currNode.getR() == null){
                currNode.setR(node);
            }else {
                insertColleague(currNode.getR(), node);
            }
        }

    }

    public void printInOrder() {
        printInOrderRecursive(root);
        //System.out.print("L: ");
        //System.out.println("R: <null>)");
    }

    private void printInOrderRecursive(BSTNode current) {
        if (current == null) {
            System.out.print("<null>");
            return;
        }
        System.out.print("(E: " + current.getC().getUserName() + " ");
        System.out.print("L: ");
        printInOrderRecursive(current.getL());
        System.out.print(" R: ");
        printInOrderRecursive(current.getR());
        System.out.print(")");
    }    
}

Answer 1

To achieve the desired output, you should modify the insertColleague method to compare the usernames in a case-insensitive manner. Instead of using compareTo, use compareToIgnoreCase when comparing the usernames. if(currNode.getC().getUserName().compareToIgnoreCase(root.getC().getUserName()) < 0)

You also need to update the printInOrder method to print the output in the desired format. Print the result in the order of (E: username L: (left subtree) R: (right subtree)) for each node in the tree.