Senior Software Engineer

Type of Service : TCP is a connection-oriented protocol. Connection-orientation means that the communicating devices should establish a connection before transmitting data and should close the connection after transmitting the data. UDP is the Datagram-oriented protocol. This is because there is no overhead for opening a connection, maintaining a connection, and terminating a connection. UDP is efficient for broadcast and multicast types of network transmission.

Reliability: TCP is reliable as it guarantees the delivery of data to the destination router. The delivery of data to the destination cannot be guaranteed in UDP.

Error checking mechanism : TCP provides extensive error-checking mechanisms. It is because it provides flow control and acknowledgment of data. UDP has only the basic error checking mechanism using checksums.

Acknowledgment : An acknowledgment segment is present in TCP. No acknowledgment segment is present in UDP.

Sequence : Sequencing of data is a feature of Transmission Control Protocol (TCP). this means that packets arrive in order at the receiver. There is no sequencing of data in UDP. If the order is required, it has to be managed by the application layer.

C++ provides an inline functions to reduce the function call overhead. Inline function is a function that is expanded in line when it is called. When the inline function is called whole code of the inline function gets inserted or substituted at the point of inline function call. This substitution is performed by the C++ compiler at compile time. Inline function may increase efficiency if it is small.

The syntax for defining the function inline is:
inline return-type function-name(parameters)
{
// function code
}

1. The struct keyword is used to define a structure. The union keyword is used to define union.

2. When the variables are declared in a structure, the compiler allocates memory to each variables member. The size of a structure is equal or greater to the sum of the sizes of each data member. When the variable is declared in the union, the compiler allocates memory to the largest size variable member. The size of a union is equal to the size of its largest data member size.
 

3. In a structure, Each variable member occupied a unique memory space. Variables members share the memory space of the largest size variable in a union.
 

4. Changing the value of a member will not affect other variables members in a structure. Changing the value of one member will also affect other variables members in a union.
 

5. Each variable member will be assessed at a time in a structure. In a union, only one variable member will be assessed at a time.
 

6. We can initialize multiple variables of a structure at a time. In union, only the first data member can be initialized.

1. The C programming language is a procedural language type while C++ is an object-oriented programming language type.
 

2. C programming follows a top to down programming approach that focuses on the steps rather than the data. C++ follows a bottom-to-top approach that focuses on data rather than the overall procedure.
 

3. Since C is a structured programming language the program is divided into separate blocks known as functions. Since C++ is an object-oriented programming language, the code is divided into Objects and Classes.

The building blocks of OOPs are : 

1. Classes & Objects : An Object can be defined as an entity that has a state and behavior. Class is basically a collection of objects which act as building blocks. 

2. Abstraction : It helps in displaying the essential features without showing the details or the functionality to the user. It avoids unnecessary information or irrelevant details and shows only that specific part which the user wants to see.
 

3. Encapsulation: The wrapping up of data and functions together in a single unit is known as encapsulation. It can be achieved by making the data members' scope private and the member function’s scope public to access these data members.
 

4. Inheritance: Inheritance is the process in which two classes have an is-a relationship among each other and objects of one class acquire properties and features of the other class. The class which inherits the features is known as the child class, and the class whose features it inherited is called the parent class.
 

5. Polymorphism: Polymorphism is defined as the ability to take more than one form. It is a feature that provides a function or an operator with more than one definition. It can be implemented using function overloading, operator overload, function overriding, virtual function

A daemon is a kind of program over UNIX-like OS that executes in the background unobtrusively, instead of upon the direct access of a user. It waits to be triggered by the appearance of a particular condition or event.
Typically, UNIX-like systems execute numerous daemons, primarily for accommodating requests for services through other systems on the network, to hardware activity, and for responding to other programs as well.
A daemon is also called background processes. It is a UNIX or Linux program that executes inside the background. Almost every daemon contains names that finish with "d" the letter. For example, sshd, this manages connections of SSH remote access, or the httpd daemon that manages the Apache server.

The grep filter searches a file for a particular pattern of characters, and displays all lines that contain that pattern. The pattern that is searched in the file is referred to as the regular expression (grep stands for global search for regular expression and print out). 
Syntax: grep [options] pattern [files]

Tip 1 : The cross questioning can go intense some time, think before you speak.

Tip 2 : Be open minded and answer whatever you are thinking, in these rounds I feel it is important to have opinion.

Tip 3 : Context of questions can be switched, pay attention to the details. It is okay to ask questions in these round, like what are the projects currently the company is investing, which team you are mentoring. How all is the work environment etc.