// удаление
void DynArr::delElem(double* arr, int pos) {
    amt--;
    double* temp = new double[amt];

    for (int i = 0; i < amt; i++) {
        if (i < pos) {
            temp[i] = arr[i];
        }
        else
            temp[i] = arr[i + 1];
    }
    arr = NULL;
    arr = temp;
    delete temp;
}