int List::indexOf(int ch)
{
    int counter = 0;
    charNode * temp = this->head;
    while (temp != NULL) {
        counter += temp->getValue();
        if (temp->getData() == ch) {
            delete temp;
            return counter - temp->getValue();
        }
        temp = temp->getNext();
    }
    delete temp;
    return -1;
}