Is smart phone necessary for a CSE student? If yes, why?

No, there is no need of smartphone for a CSE student. But, still if you want to buy a smartphone the specification as follows: RAM: 3 GB or above Display: 5.5" Internal Storage: 32GB OS: Android.

These days, you need you upgrade yourself by updating, as you are CSE student and you are a student. You need to update yourself, and it is not necessary to buy costly phone just go for simple 4 g smart phones with 2 gb RAM that will be enough for you.