Written Test... Categories
Programming related in C++ -- OOP,debugging, prediction of output etc
DAtabase
Operating System
data structures.

Gpa criteria not must but you should keep a good gpa.

Only Technical
Make a stack with 2 queues
Sorting related
Linux commands
opreating system and networking ones also

LR parse of function pointer (for oracle).

In interview
Be confident, don't put pressure on yourself by giving too much importance , Its better to say that you don't know an answer than making up one
Learn about the company, reviewing core courses is a must.

Written Test... Categories
Programming related in C++ -- OOP,debugging, prediction of output etc
DAtabase
Operating System
data structures

Interview...

Programming Test
Not too tough... easy for regular programmers
Gpa definitely big factor. All selected for interview performed equally well.
Knowledge of linux commands might have helped as well.