int list_del(list_head *list, int i){
    if(list==NULL){
        return 0;
    }
    int pos=1;
    list_node *prev = NULL;
    list_node *current = list->head;
    list_node *next = current->next;
    while(current!=NULL){
        if(pos==i && pos==1){
            free(current->data);
            free(current);
            list->head = next;
            list->list_size--;
            return 1;
        }
        if(pos==i && pos==list->list_size){
            free(current->data);
            free(current);
            prev->next = NULL;
            list->list_size--;
            return 1;
        }
        if(pos==i){
            free(current->data);
            free(current);
            prev->next = next;
            list->list_size--;
            return 1;
        }
        pos++;
        prev = current;
        current = current->next;
        next = current->next;
    }
    return 0;
}