Searching A Binary Search Tree

#include<iostream>
#include<vector>
using namespace std;

class Node {

    public:
    int data;
    Node * left;
    Node * right;
    Node(int x) : data(x), left(NULL), right(NULL)
    {}
};

class Tree {

    public:

    vector<int> order;

    /* The in-order traversal of a valid binary search tree is always in increasing order (sorted) */
    void InOrder(Node * node) {

        if (node != NULL) {
            InOrder(node->left);
            cout << node->data << " ";
            order.push_back(node->data);
            InOrder(node->right);
        }
    }

    Node * SearchBST(Node * root, int data) {
        if (root == NULL or root->data == data) {
            return root;
        } else if (root->data < data) {
            return SearchBST(root->right, data);
        } else if (root->data > data) {
            return SearchBST(root->left, data);
        }
        return NULL;
    }
};

int main() {

    /*   6 
        / \
       4   9  */

    Node * root1 = new Node(6);
    root1->left = new Node(4);
    root1->right = new Node(9);

    Tree t;
    int data = 9;
    if (t.SearchBST(root1, data) != NULL) {
        cout << "Node " << data << " found" << endl;
    }

    /*   5
        / \
       1   7  
            \
             8  */
    Node * root2 = new Node(5);
    root2->left = new Node(1);
    root2->right = new Node(7);
    root2->right->right = new Node(8);

    data = 7;
    if (t.SearchBST(root2, data) != NULL) {
        cout << "Node " << data << " found" << endl;
    }
    data = 10;
    if (t.SearchBST(root2, data) != NULL) {
        cout << "Node " << data << " found" << endl;
    }

    return 0;
}

Node 9 found.
Node 7 found.
Node 10 not found.