I got selected in TCS during my final year B.Sc CS. I don't have even a single certification. The questions for me were:-
1.Write a sorting program in C.
2.Is it possible to create your own header files in C?.
3.Write the truth table for EX-OR gate.
4.What is the command in unix for listing all files in a directory?
5.Explain how the computer manages memory.
6.What is round robin?
7.What is a dead lock?
8.What is encapsulation in C++?
9.What are constructors & destructors in C++?
I answered all questions except 5th.

So as plasma_snake has already said they mostly look for the basic & clarity of knowledge the candidate has. Thanx