.....

template <typename T>
box<T>* combineBoxes(box<T>* sorted, box<T>* toAdd) {
    if (!sorted || !toAdd) {
        return nullptr;
    }
    box<T>* result = nullptr;
    box<T>* tempSorted = sorted;
    while (tempSorted != nullptr) {
        push_back(result, tempSorted->data);
        tempSorted = tempSorted->next;
    }

    box<T>* tempToAdd = toAdd;
    tempSorted = result;
    while (tempToAdd != nullptr) {
        size_t index = 0;
        bool elementAdded = false;
        while (tempSorted != nullptr) {
            if (tempSorted->data >= tempToAdd->data) {
                insertAt(result, tempToAdd->data, index);
                elementAdded = true;
                break;
            }
            tempSorted = tempSorted->next;
            index++;
        }
        if (!elementAdded) {
            push_back(result, tempToAdd->data);
        }
        tempSorted = result;
        tempToAdd = tempToAdd->next;
    }

    return result;

}