void LCD::DeleteLCD(string &producator) {
    LCD *q = headLCD;
    if (headLCD->ReturnProducator() == producator) {
        headLCD = headLCD->next;
        delete q;
        return;
    }
    while (q->next != NULL && q->ReturnProducator() != producator) q = q->next;
    if (q->next) {
        LCD *p = q->next;
        q->next = q->next->next;
        delete p;
    }
    else
        cout << "\n Monitorul nu exista in baza de date";
}