C++

What is encapsulation? Hiding data

What is virtual function table? How is it used? Ans: Dynamic Binding

Explain vptr, and how it is used.

Do we have a virtual constructor? Why not? NO

Why do we need a virtual destructor?

Can abstract class pointer be called on its derived class object methods? YES

What are the differences between C++11 and C++98?

What is object slicing?

What are different cast in C++? Static_cast, dynamic_cast,const_cast, and reinterpret_cast?When is each used?

What are the default constructor that C++ provides?

REMEMBER:

What happens when we write only a copy constructor – does compiler create default constructor?

Compiler doesn’t create a default constructor if we write any constructor even if it is copy constructor. For example, the following program doesn’t compile.

TCP:

What is 3 way handshake?

Can somone eavsdrop on TCP communication?

What is the difference between flow control and congestion control in TCP?

How can TCP be made secure? ANS: By using SSL on top

Why do we have public key and a private key in SSL?

How do you achieve reliability in UDP? ANS: gave e.g. of RTCP in RTP scenario

Why is UDP not reliable? It's faster coz of lack of ACKs

1)Implement memmove() or memcpy() when there's memory overlap? Copy from reverse

2) An object declared on stack does not use vptr;

3)How would you Implement a periodic sequence like this. The function should be self-contained.

The below should return false as soon as you determine the sequqnce is not periodic.

Assume the numbers within a sequence are unique. And max length of sequence is 128.

#define MAX_NUM 128

bool func(int x){

}

4) Using -1 using XOR

5) Removing an element in linkedlist with just pointer to it

6) task Queue problem. Producer-consumer problem. Have a unit of work to be done. Multiple elements doing it.