Simple Binary Tree (in class code)

BinTree.cc

#include <iostream>
#include <iomanip>
#include <cmath>
#include <stack>
#include <array>
#include <utility>
#include <cstdlib>
#include <ctime>
using namespace std;

class Node {
    Node();
    int data;
    Node* left;
    Node* right;
};

Node::Node() {
    left = NULL;
    right = NULL;
}

//Depth of a tree: starts at 0

class BinTree {
private:
    Node* root = NULL;
    void printNodeInOrder(Node* n);
    void delNode(Node* n);
public:
    void insert(int data);
    void printInOrder();
};

int main() {
    BinTree test;
    test.insert(50);
    test.insert(55);
    test.insert(45);
    test.insert(23);
    test.insert(85);
    test.insert(53);
    test.printInOrder();
}

void BinTree::insert(int data) {
    Node* nn = new Node;
    nn->data = data;

    if (root == NULL)
    {
        root = nn;
        return;
    }
    else
    {
        Node* current = root;
        Node* parent;

        //find the parent of nn
        while (current != NULL)
        {
            parent = current;
            if (nn->data < current->data)
                current = current->left;
            else if (nn->data > current->data)
                current = current->right;
            else
            {
                delete nn;
                return;
            }
        }

        //adjust parent pointers
        if (nn->data < parent->data)
            parent->left = nn;
        else
            parent->right = nn;
    }
}

void BinTree::printNodeInOrder(Node* n) {
    if (n != NULL)
    {
        printNodeInOrder(n->left);
        cout << n->data << '\n';
        printNodeInOrder(n->right);
    }
}

void BinTree::printInOrder() {
    printNodeInOrder(root);
}

void BinTree::delNode(Node* n) {
    if (n != NULL)
    {
        delNode(n->left);
        delNode(n->right);
        delete n;
    }
}