Find children of a given binary tree by target node or by target value

Using Target Node:

To print the children of a given binary tree node in Java, you can use a recursive approach. Here's an example code snippet that demonstrates this:

class Node {
    int data;
    Node left, right;

    public Node(int item) {
        data = item;
        left = right = null;
    }
}

class BinaryTree {
    Node root;

    public BinaryTree() {
        root = null;
    }

    // Function to print the children of a given node
    void printChildren(Node node) {
        if (node == null) {
            System.out.println("Node is null");
            return;
        }

        if (node.left != null)
            System.out.println("Left child: " + node.left.data);
        else
            System.out.println("No left child");

        if (node.right != null)
            System.out.println("Right child: " + node.right.data);
        else
            System.out.println("No right child");
    }

    public static void main(String[] args) {
        BinaryTree tree = new BinaryTree();
        tree.root = new Node(1);
        tree.root.left = new Node(2);
        tree.root.right = new Node(3);
        tree.root.left.left = new Node(4);
        tree.root.left.right = new Node(5);

        Node targetNode = tree.root.left;
        tree.printChildren(targetNode);
    }
}

In this example, the Node class represents a binary tree node with a data value and references to the left and right child nodes. The BinaryTree class has a method printChildren that takes a node as input and prints its left and right children if they exist.

In the main method, we create a binary tree and assign values to its nodes. Then, we define a targetNode variable that represents the node for which we want to print the children. Finally, we call printChildren method with targetNode as an argument to print its children.

Using Target Node Value:

To print the children of a given binary tree node value in Java, you can modify the previous code snippet to search for the node with the specified value and then print its children. Here's an updated version of the code:

class Node {
    int data;
    Node left, right;

    public Node(int item) {
        data = item;
        left = right = null;
    }
}

class BinaryTree {
    Node root;

    public BinaryTree() {
        root = null;
    }

    // Function to search for a node with a given value
    Node searchNode(Node node, int value) {
        if (node == null || node.data == value)
            return node;

        // Recursively search in the left and right subtrees
        Node leftResult = searchNode(node.left, value);
        if (leftResult != null)
            return leftResult;

        Node rightResult = searchNode(node.right, value);
        if (rightResult != null)
            return rightResult;

        return null;
    }

    // Function to print the children of a given node
    void printChildren(int value) {
        Node targetNode = searchNode(root, value);
        if (targetNode == null) {
            System.out.println("Node with value " + value + " not found");
            return;
        }

        if (targetNode.left != null)
            System.out.println("Left child: " + targetNode.left.data);
        else
            System.out.println("No left child");

        if (targetNode.right != null)
            System.out.println("Right child: " + targetNode.right.data);
        else
            System.out.println("No right child");
    }

    public static void main(String[] args) {
        BinaryTree tree = new BinaryTree();
        tree.root = new Node(1);
        tree.root.left = new Node(2);
        tree.root.right = new Node(3);
        tree.root.left.left = new Node(4);
        tree.root.left.right = new Node(5);

        int targetValue = 2;
        tree.printChildren(targetValue);
    }
}

In this updated code, we added a new method searchNode that recursively searches for a node with the specified value in the binary tree. It returns the node if found, or null otherwise.

In the printChildren method, we first call searchNode to find the node with the given value. If the node is found, we print its left and right children (if they exist) as before. If the node is not found, we print a message indicating that the node was not found.

In the main method, we create a binary tree and assign values to its nodes. Then, we define a targetValue variable that represents the value of the node for which we want to print the children. Finally, we call printChildren method with targetValue as an argument to print the children of the node with that value.