void DoubleLinked::AddAfter(Date elem, Date after)
{
    Node *temp = (Node*)malloc(sizeof(Node));
    temp->elem = elem;

    Node* findAfterNode = find(after);

    if (head == NULL) {
        temp->Prev = NULL;
        head = tail = temp;
        return;
    }
    if (findAfterNode != NULL && findAfterNode != tail) {
        temp->Next = findAfterNode->Next;
        temp->Prev = findAfterNode;
        findAfterNode->Next->Prev = temp;
        findAfterNode->Next = temp;
    }
    else if (findAfterNode != NULL && findAfterNode == tail) {
        temp->Next = NULL;
        temp->Prev = findAfterNode;
        tail = temp;
        findAfterNode->Next = temp;
    }
}

void DoubleLinked::AddBefore(Date elem, Date before)
{
    Node *temp = (Node*)malloc(sizeof(Node));
    temp->elem = elem;

    Node* findAfterNode = find(before);

    if (head == NULL) {
        temp->Prev = NULL;
        head = tail = temp;
        return;
    }
    if (findAfterNode != NULL && findAfterNode != head) {
        temp->Next = findAfterNode;
        temp->Prev = findAfterNode->Prev;
        findAfterNode->Prev->Next = temp;
        findAfterNode->Prev = temp;
    }
    else if (findAfterNode != NULL && findAfterNode == head) {
        temp->Next = findAfterNode;
        temp->Prev = NULL;
        head = temp;
        findAfterNode->Prev = temp;
    }
}