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;
    }
};
//insert nodes into tree
void insert(TreeNode*& root, int value) {
    if (root == nullptr) {
        root = new TreeNode(value);
    }
    else if (value < root->data) {
        insert(root->left, value);
    }
    else {
        insert(root->right, value);
    }
}
//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 = nullptr;
    int n;
    std::cout << "Enter the number of nodes you will insert: ";
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        int value;
        std::cout << "Enter a value: ";
        std::cin >> value;
        insert(root, value);
    }
    printPreOrder(root);
}