Y1S2 Find Parent in Binary Tree Homework

#include <iostream>
using namespace std;

struct tree {
    int key;
    tree* left, * right;
};

tree* newNode(int val) {
    tree* newNode = new tree();
    newNode->key = val;
    newNode->left = newNode->right = NULL;
    return newNode;
}

tree* insertNode(tree* root, int val) {
    if (root == NULL)
        root = newNode(val);
    else if (val <= root->key)
        root->left = insertNode(root->left, val);
    else
        root->right = insertNode(root->right, val);
    return root;
}

void searchParent(tree* root, int val, int parent) {
    if (root == NULL)
        return;
    if (root->key == val)
        cout << parent;
    else {
        searchParent(root->left, val, root->key);
        searchParent(root->right, val, root->key);
    }
}

int main() {
    tree* root = NULL;
    int x, val1, val2;
    cout << "How many nodes to add to tree: ";
    cin >> x;
    for (int i = 0; i < x; i++) {
        cout << "Key for node " << i + 1 << ": ";
        cin >> val1;
        root = insertNode(root, val1);
    }
    cout << "Find parent of: ";
    cin >> val2;
    searchParent(root, val2, -1);
    return 0;
}