int delete_user(const char *name, User **user_ptr_del) {
    if (strcmp((*user_ptr_del)->name, name) == 0){
            int i = 0;
                    while (((*user_ptr_del)->friends[i] != NULL) && (i < MAX_FRIENDS)){
                        int j = 0;
                                while (((*user_ptr_del)->friends[i]->friends[j] != NULL) && (j < MAX_FRIENDS)){
                                if (strcmp(((*user_ptr_del)->friends[i]->friends[j]->name), name)== 0){
                                        (*user_ptr_del)->friends[i]->friends[j] = (*user_ptr_del)->friends[i]->friends[j+1];
                                        }
                                j++;
                                }
                                i++;
                        }
                (*user_ptr_del) = (*user_ptr_del)->next;
                return 0;
                }

delete the first user From the list pointed to by *user_ptr_del