Dear Aspirant 

Both the branch have their own scope, you will be successful even if you are interested in any one of them so I would like to tell you that computer science engineering is not a core branch but it has high demand of engineers in private sector industries than the engineers of any other branch. 

While electronic and communication engineering is a core branch and from this you can not only get job in public sector industry but also in private sector like computer science engineering just by learning programming skill and other skills required for computer science engineering student. So it has core as well as non core opportunities. 

So choose smartly considering my views.

Good luck for your future :) 

Feel free to ask if you have any further queries.