BTree.java

package Flawless_Feedback;

//Source:  http://www.newthinktank.com/2013/03/binary-tree-in-java/
// New Think Tank


public class BTree {
    BNode root;
    String temp = "";

    public void addNode(int key, String name) {

        // Create a new Node and initialize it

        BNode newNode = new BNode(key, name);

        // If there is no root this becomes root

        if (root == null) {

            root = newNode;

        } else {

            // Set root as the Node we will start
            // with as we traverse the tree

            BNode focusNode = root;

            // Future parent for our new Node

            BNode parent;

            while (true) {

                // root is the top parent so we start
                // there

                parent = focusNode;

                // Check if the new node should go on
                // the left side of the parent node

                if (key < focusNode.key) {

                    // Switch focus to the left child

                    focusNode = focusNode.leftChild;

                    // If the left child has no children

                    if (focusNode == null) {

                        // then place the new node on the left of it

                        parent.leftChild = newNode;
                        return; // All Done

                    }

                } else { // If we get here put the node on the right

                    focusNode = focusNode.rightChild;

                    // If the right child has no children

                    if (focusNode == null) {

                        // then place the new node on the right of it

                        parent.rightChild = newNode;
                        return; // All Done

                    }

                }

            }
        }

    }

    // All nodes are visited in ascending order
    // Recursion is used to go to one node and
    // then go to its child nodes and so forth

    public String inOrderTraverseTree(BNode focusNode) {
        temp = "";
        if (focusNode != null) {

            // Traverse the left node
            temp += inOrderTraverseTree(focusNode.leftChild);

            // Visit the currently focused on node
            temp += focusNode + ", ";

            // Traverse the right node
            temp += inOrderTraverseTree(focusNode.rightChild);

            return temp;
        }
        return "";
    }

    public String preorderTraverseTree(BNode focusNode) {
        temp = "";
        if (focusNode != null) {

            temp += focusNode + ", ";

            temp += preorderTraverseTree(focusNode.leftChild);
            temp += preorderTraverseTree(focusNode.rightChild);

            return temp;
        }
        return "";
    }

    public String postOrderTraverseTree(BNode focusNode) {
        temp = "";
        if (focusNode != null) {

            temp += postOrderTraverseTree(focusNode.leftChild);
            temp += postOrderTraverseTree(focusNode.rightChild);

            temp += focusNode + ", ";

            return temp;
        }
        return "";
    }

    public BNode findNode(int key) {

        // Start at the top of the tree

        BNode focusNode = root;

        // While we haven't found the Node
        // keep looking

        while (focusNode.key != key) {

            // If we should search to the left

            if (key < focusNode.key) {

                // Shift the focus Node to the left child

                focusNode = focusNode.leftChild;

            } else {

                // Shift the focus Node to the right child

                focusNode = focusNode.rightChild;

            }

            // The node wasn't found

            if (focusNode == null)
                return null;

        }

        return focusNode;

    }
}

//    public static void main(String[] args) {
//
//        BinaryTree theTree = new BinaryTree();
//
//        theTree.addNode(50, "Boss");
//
//        theTree.addNode(25, "Vice President");
//
//        theTree.addNode(15, "Office Manager");
//
//        theTree.addNode(30, "Secretary");
//
//        theTree.addNode(75, "Sales Manager");
//
//        theTree.addNode(85, "Salesman 1");
//
//        // Different ways to traverse binary trees
//
//        // theTree.inOrderTraverseTree(theTree.root);
//
//        // theTree.preorderTraverseTree(theTree.root);
//
//        // theTree.postOrderTraverseTree(theTree.root);
//
//        // Find the node with key 75
//
//        System.out.println("\nNode with the key 75");
//
//        System.out.println(theTree.findNode(75));
//
//    }


class BNode {

    int key;
    String name;

    BNode leftChild;
    BNode rightChild;

    BNode(int key, String name) {

        this.key = key;
        this.name = name;

    }

    public String toString() {

        return key + "-" + name;

        /*
         * return name + " has the key " + key + "\nLeft Child: " + leftChild +
         * "\nRight Child: " + rightChild + "\n";
         */

    }

}