Hello Manender,

It depends on your qualification. For B.Tech CSE, either you need to have studied Mathematics, Physics and Chemistry in your 10+2, or you should be a diploma holder in Computer Science Engineering from a recognised board. So, being a mechanical engineering diploma holder, you do not seem to be eligible for B.Tech in CSE. However, if you have studied the above subjects in your 12th, you can sit for entrance exams all over again to get into colleges offering B.Tech CSE.

All the Best!