tree

#include <iostream>
#include <time.h>

using namespace std;

struct Tree {
    string name;
    string number;
    Tree* right = NULL;
    Tree* left = NULL;
};

Tree* Add(string aName, string aNumber, Tree* root) {// * - a iaei? noai?eii iiea??ee ia ei??iu aa?aaa, & - uia i?ao?aaoe c i?ea?iaeii ? ci?i?aaoe eiai
    if (root == NULL) {
        root = new Tree;
        root->name = aName;
        root->number = aNumber;
        return root;
    }
    if (aName > root->name) {
        root->right = Add(aName, aNumber, root->right);
    }
    else {
        root->left = Add(aName, aNumber, root->left);
    }
    return root;
}

string Search(string aName, Tree* root) {// iiea??ee ia ei??iu
    if (root == NULL) {
        return "This name isn`t in list";
    }
    if (aName == root->name) {
        return root->number;
    }
    if (aName > root->name) {
        return Search(aName, root->right);
    }
    return Search(aName, root->left);
}

Tree* SearchMin(Tree* root) {
    if (root->left) {
        return SearchMin(root->left);
    }
    return root;
}

Tree* Delete(string aName, Tree* root) {
    if (root == NULL) {
        cout<<"This name isn`t in list"<<endl;
        return root;
    }
    if (root->name == aName) {
        if (root->left && root->right) {
            Tree* min = SearchMin(root->right);
            root->name = min->name;
            root->number = min->number;
            root->right = Delete(min->name, root->right);
            return root;
        }
        if (root->left) {
            root->name = root->left->name;
            root->number = root->left->number;
            root->left = Delete(root->left->name, root->left);
            return root;
        }
        if (root->right) {
            root->name = root->right->name;
            root->number = root->right->number;
            root->right = Delete(root->right->name, root->right);
            return root;
        }
        root = NULL;
        return root;
    }
    if (root->name > aName) {
        root->right = Delete(aName, root->right);
    }
    else {
        root->left = Delete(aName, root->left);
    }
    return root;
}

int main() {
    Tree* a = NULL;

    a = Add("Nik", "123456", a);
    a = Add("Onf", "234567", a);
    a = Add("Dih", "4637468274", a);

    cout << Search("Nik", a) << endl;
    cout << Search("Onf", a) << endl;
    cout << Search("Dih", a) << endl;

    a = Delete("Nik", a);

    if (!a) cout << "null" << endl;

    cout << Search("Nik", a) << endl;
    cout << Search("Onf", a) << endl;
    cout << Search("Dih", a) << endl;

    a = Delete("Onf", a);

    cout << Search("Nik", a) << endl;
    cout << Search("Onf", a) << endl;
    cout << Search("Dih", a) << endl;

    a = Delete("Dih", a);

    cout << Search("Nik", a) << endl;
    cout << Search("Onf", a) << endl;
    cout << Search("Dih", a) << endl;

    return 0;
}