void List::read(FILE *f){
    int v;
    char buf[LEN];

    if (fscanf(f, "%s%d", buf, &v) != 2){
        if (!feof(f)){
            throw "read error";
            return;
        }
        throw "no elements in file";
        return;
    }
    curr = new Node(buf, v);
    head = curr;
    for(Node *prv = curr;;curr = curr->next, curr->prev = prv, prv = curr){
        if (fscanf(f, "%s%d", buf, &v) != 2){
            if (!feof(f)){
                throw "read error";
                return;
            }
            return;
        }
        Node *nxt = new Node(buf, v);
        curr->next = nxt;
    }
    return;
}