Program to Perform the Inorder Tree Traversal

// Node class representing a single node of a binary tree
class Node {
    int data;  // Data element stored in the node
    Node left, right;  // Pointers to left and right child

    // Constructor to create a new node with given data
    public Node(int item) {
        data = item;
        left = right = null;  // Initially, left and right children are set to null
    }
}

// BinaryTree class that defines a binary tree
class BinaryTree {
    Node root;  // Root of the binary tree

    // Constructor to create an empty binary tree with root set to null
    BinaryTree() {
        root = null;
    }

    // Recursive function to perform inorder traversal of the tree
    void inorderTraversal(Node node) {
        if (node == null)
            return;  // Base case: if current node is null, return

        inorderTraversal(node.left);  // Recursively traverse the left subtree
        System.out.print(node.data + " ");  // Visit the current node (print the node's data)
        inorderTraversal(node.right);  // Recursively traverse the right subtree
    }

    // Main method to run the code
    public static void main(String[] args) {
        BinaryTree tree = new BinaryTree();  // Create an instance of BinaryTree
        tree.root = new Node(1);  // Set root of the tree
        tree.root.left = new Node(2);  // Set left child of root
        tree.root.right = new Node(3);  // Set right child of root
        tree.root.left.left = new Node(4);  // Set left child of node 2
        tree.root.left.right = new Node(5);  // Set right child of node 2

        // Perform inorder traversal and print the output
        System.out.println("Inorder traversal of binary tree is: ");
        tree.inorderTraversal(tree.root);
    }
}