Practika_24.01.2021 + drugoi kod smes REDAKTIROVAN

////////////////
Node * List::Del_By_value() {
    Node * hv = head;
    Node * v1 = head;
    Node * v2 = head;
    Node * v3 = head;
    Node * tail = head;

    string value_del;
    cin >> value_del;
    if (hv == NULL) {
        cout << "pusto \n";
        return NULL;
    } // В списке нет узлов
    else if (tail->ptr==NULL) {
        if (v2->LastName == value_del) {
            head_del(); cout << "Ostalos 0 uslov \n";
            return NULL;
        }
        return NULL;
    } // В списке нет узлов
    while (tail->ptr != NULL) {
        tail = tail->ptr;
    }
    if (v2->LastName == value_del) {
        head_del();
        return NULL;
    }
    else if (tail->LastName == value_del) {
        Delete_end();
        return NULL;
    }
    else {

        int j = 0;
        while (hv != NULL) {
            v1 = hv;
            v2 = v1->ptr;
            v3 = v2->ptr;
            if (v3 == NULL) { break; }
            if (v2->LastName == value_del) {
                //// <operation>
                v1->ptr = v3;
                delete v2;
                //// </operation>
                break;
            }
            hv = hv->ptr;
            j++;
        }
    }
}
///////////////////