Sir,
I am a computer science student and completed my b.e. I want to know a proper answer for a visa interview question "How do I know you'll come back after your education" because this is the most recently asked question in interviews.

Answer it truthfully and by telling the interviewer your plans in detail after you obtain your education. If you are honestly going to return, than you should have no problem detailing your plans, and perhaps already have some of your plan in motion or at least prepared for your interview.