>what is a trie?....
A search tree that stores common prefixes in internal nodes, and the prefixes have some form of lexographical order. A search is done by matching the prefix nodes until you reach a leaf, which has the complete string. It's a surprisingly powerful data structure.
>i need complete data structure of trie...............and how to implement it????
That's not helping, that's doing it for you. We're not your personal homework service.