Constructed Binary Tree(Pre-order traversal)

#include <iostream>

struct TreeNode {
    int data;           //node value
    TreeNode* left;     //pointer to left child
    TreeNode* right;    //pointer to right child

    TreeNode(int value) {   //constructor for initializing a node
        data = value;
        left = nullptr;
        right = nullptr;
    }
};
//Pre-order traversal - you start at the root node and then you visit the left subtree first and then the right
void printPreOrder(TreeNode* root) {
    if (root != nullptr) {
        std::cout << root->data << " ";
        printPreOrder(root->left);
        printPreOrder(root->right);
    }
}
int main()
{
    TreeNode* root = new TreeNode(1);
    root->left = new TreeNode(3);
    root->right = new TreeNode(4);
    root->left->left = new TreeNode(5);
    root->left->right = new TreeNode(8);

    printPreOrder(root);
}
//          1
//         / \
//        3   4
//       / \
//      5   8