Lecture 283:- Preorder Tree Traversal

Preorder tree traversal is a depth-first traversal method in which the nodes are visited in the order: Root -> Left -> Right. Here's a C++ implementation of preorder traversal for a binary tree:

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#include <iostream> struct Node {    int data;    Node* left;    Node* right;    Node(int val) {        data = val;        left = nullptr;        right = nullptr;    } }; // Preorder Traversal void preorderTraversal(Node* root) {    if (root) {        std::cout << root->data << " ";        preorderTraversal(root->left);        preorderTraversal(root->right);    } } int main() {    // Create a binary tree:    //        1    //       / \    //      2   3    //     / \    //    4   5    Node* root = new Node(1);    root->left = new Node(2);    root->right = new Node(3);    root->left->left = new Node(4);    root->left->right = new Node(5);    // Perform preorder traversal    std::cout << "Preorder Traversal: ";    preorderTraversal(root);    std::cout << std::endl;    // Remember to free the allocated memory after use to avoid memory leaks.    delete root->left->left;    delete root->left->right;    delete root->left;    delete root->right;    delete root;    return 0; }

In this implementation, we define a Node struct to represent the nodes of the binary tree. The preorderTraversal function performs the preorder traversal by printing the data of the current node, then recursively calling the function for the left subtree, and finally for the right subtree.

Output:

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Preorder Traversal: 1 2 4 5 3

The output shows the nodes visited in the preorder traversal order: 1 -> 2 -> 4 -> 5 -> 3.