Programming my own controller For Quad Copter

i wanna write my own controller of quad copter in Java(that code use in android app) i need guide lines where to start and how to start.Please tell me the pseudo code steps.i am at beginner level.

Programming your own controller is not a simple task especially if you are a beginner in programming. But the best place to start would be to look at the crazyflie project, as its a relatively simple flight controller with code that is well written and documented to make it easy to work with. There is also code for an andorid app to control the drone from your phone, you can see the code on github

i am good in programming but not know how to start