CareerCup

use tries

You will have a class called Entry:
>phone_number: int
>name: string
>details of that person like email, address, alternate number....
>Two child objects of Entry - Entry Left, Entry Right

Then there will be a class called Phonebook
It will have a BST on this structure and use foll functioins:
void insert(Elem elem);
int delete(Elem elem); //return true if elem found and delete
Elem search(String Name);//or number
int update(Elem elem);
void display();

the main adv of storing in BST will be that while displaying alphabetically, u wont need to sort them.

other class can be groups:
to store some groups like friends, relatives, project__1, ...
each of them will have a linked list of the specified Element objects.
Members:
group_name;
List list;
sendToAll();
/* */

Hashtable?

Can use a data structure called Trie.. for more info read wiki link

Cant we use trie and hash map. trie for searching and hashmap which uses the name as key for other details.