how to develop trading platform for bitcoin I would like to know how to start developing trading platform for BTC,LTC where the user can create his wallet, send and receive coins, Buy and sell coins.

i have checked the trading platforms and i know what needs to be done. But BTC has open source code. if anyone has used it and know whether it would be better to go with BTC open source or an api.    

can anyone guide me in starting this.

Thanks
Start by looking at existing trading platforms. Decide what features you want to have. Then think about what data you'll need to store and design a database schema. Then begin writing the code to perform your business logic using the database schema. Last, put a front end on it and invite people to test it.