Infosys Syllabus 2018 and Online Test

Most asked Technical Questions in Infosys

What is the difference between C and Java?

Java is the object-oriented programming language whereas C is the procedural language.
Java supports method overloading whereas C does not support overloading at all.
If an error occurs there is a concept called exception handling which is there in Java but in C there is no concept like that.
Java does not support preprocessors but C does.
If the memory is allocated in C it has to be freed with the help of malloc() or free() library calls but Java uses the garbage collector to delete the objects that are no longer have any reference to them.

So prepare not only the difference between C and Java but also other differences between every other programming languages because there is a huge possibility of those questions to be asked in the interview.

Explain the OOP concepts in C++.

Object-oriented programming main concept is to implement real-world entities and binds data and functions which operate on them so that no other part of the code can access the data except that function. Also explain the objects, class, inheritance, polymorphism, encapsulation, and abstraction. Usually, everyone knows the basic definition but when it comes to giving real-world examples, they struggle. Hence, make sure that you can provide some real-world examples which you can relate to.

Objects

Objects are runtime entity with some characteristics. For example, we can take fruits like banana, apple, oranges here. Each and every fruit has some characteristics like different shape, colour, odour. This is what we call as objects.

Class

Class is a user-defined data type and it is the blueprint of data and functions. We can take the same example fruits. Here, the fruit is the class and the different types of fruits which are available are the objects because within the class the objects are defined. So we can say that the instance of the class is an object.

Inheritance

Deriving the properties of the base class from the derived class is known as Inheritance. Here we can take an example of a parent and the child. All the properties of the father are inherited by son because of the gene factor which is present. There is a famous quote saying “Like Father Like Son”.

Polymorphism

The process of representing one form in many other forms is called Polymorphism. Take yourself as an example. You behave like son in the home. If you are going to a shopping mall then you behave like a customer. In school, you behave like a student. So this is what is known as polymorphism taking different forms.

Encapsulation

Encapsulation is the process of wrapping up of data and methods in a single unit. Here we can take an example as a capsule. In the capsule, the medicine is present only inside.

Abstraction

Abstraction is the process of hiding the internal details to protect from unauthorized access and only the external appearance is known. We can take mobile as an example. We only know how to operate the mobile but don’t know the internal workings of it.

So these are the OOP concepts with real time examples. But try to know the details of how it is used in the program and also you can write a program as the example and show it to them. This concept is same in Java also and this is the most important question in interviews. So basically compare and study it will be very easy and you will not forget the concept.

What is Platform Independent?

Platform independent means it can run on any OS without even changing the source code again and again. So once you write your code, you need not modify it according to the OS in platform independent languages. Java is platform independent, not C or C++.

What is Preprocessor in C/C++?

Preprocessors are programs that process your code before the compilation. Preprocessor programs are available which provides preprocessor directives and tells the compiler to preprocess the code before compiling and it begins with the # symbol.

What is a linked list?

A linked list is a linear data structure where each element is separated in an object and each element consists of two items, one is data and a reference to the next node actually the address. The last node refers to NULL.

What do you know about UNIX and DOS?

First, DOS and UNIX are two operating systems. DOS does not have a GUI, so it is restricted to command line whereas UNIX has its own GUI. UNIX is case sensitive whereas DOS is not. DOS uses backslashes (\) to separate directories and UNIX use forward slashes(/) to separate directory. UNIX is used mainly in servers and DOS is an embedded system.

What is the difference between socket and session?

The socket is the combination of both IP address and port numbers in pairs. The session is just a logical connectivity between the source and the destination.

What is Normalisation?

Normalisation is the process of organizing the data in the database basically to remove the redundant data i.e. Copy of the data and make sure that only related data got stored in the table. The types of Normalisation are as follows:

First Normal Form (1NF): The 1NF rules for an organized database are as follows:
Eliminate duplicative columns from the same table.
Create separate tables for each group of related data and identify each row with a unique column or set of columns (the primary key).

Second Normal Form (2NF): Once the database is organized according to the 1NF rules, 2NF rules further addresses the concept of removing duplicative data. These rules are as follows:
Meet all the requirements of 1NF.
Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
Create relationships between these new tables and their predecessors through the use of foreign keys.

Third Normal Form (3NF): The 3NF rules are as follows:
Meet all the requirements of 2NF.
Remove columns that are not dependent upon the primary key.

Primary Key: During the design phase of the database, architects delineate entities and how these entities related to each other. Delineation provides the basis for all Relational Database Management Systems (RDBMS) design. Each entity should have its own unique identifier, which is known as the primary key. 

Boyce-Codd Normal Form (BCNF or 3.5NF):: It also referred to as the “third and half (3.5) normal form” as adds one more requirement to the 3NF rule. The 3.5NF rules are as follows:
Meet all the requirements of the third normal form.
Every determinant must be a candidate key.

Fourth Normal Form (4NF): The rules for the 4NF are as follows:
Meet all the requirements of the third normal form.
A relation is in 4NF if it has no multi-valued dependencies.

In a DBMS, a trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs. Since triggers are event-driven specialized procedures, they are stored in and managed by the DBMS. A trigger cannot be called or executed; the DBMS automatically fires the trigger as a result of a data modification to the associated table. Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. Each trigger is attached to a single, specified table in the database. 

What is database schema?

The database schema is a set of formulae which are called integrity constraints imposed in a database. The different levels of Database Schema are as follows:

Conceptual schema: a map of concepts and their relationships.
Logical schema: a map of entities and their attributes and relations
Physical schema: a particular implementation of a logical schema
Schema object: Oracle database object

What is a null pointer?

In computer programming, a null pointer is a pointer that does not point to any object or function.

What do you mean by Object-Relational DBMS or ORD?

An object-relational database (ORD) or object-relational database management system (ORDBMS), is a database management system (DBMS) similar to a relational database, but with an object-oriented database model consisting of objects, classes and inheritance. These Object Oriented components are directly supported in database schemas of an ORD/ ORDBMS and in the query language. In addition, just as with proper relational systems, it supports extension (custom data-types and methods) of the data model.

What is Data Link Control and what is the main purpose of the Data Link Control Monitor?

Data Link Control or DLC is the service provided by the Data Link layer of the function defined in the Open Systems Interconnection (OSI) model for network communication. The Data Link layer is responsible for providing reliable data transfer across one physical link within the network. Some of its primary functions include defining frames, performing error detection on those frames, and performing flow control to prevent a fast sender from overwhelming a slow receiver by sending many packets continuously.

You will be asked to write a specific or a random program.

This is also one of the common Infosys technical interview questions. So mention the programming language which you know in the resume and don’t try to claim to know a language that you don’t know in the resume as you may be caught. Try to know all the basic programs like swapping, arrays, etc. Practice it by writing and don’t just like that memorise it. Try to understand the concept. It does not matter if you know Java or C++ because the concept is the same for all programs. The only thing that changes is the syntax.

Explain your project.

This is the sure Infosys technical interview question asked to every candidate. So, be prepared to talk about the project you have done and try to explain them in a way that they can easily understand it. Even if they ask you to write the code of the project you should have the ability to at least explain the logic in detail.

They can ask General Questions based on technical like

What is the most difficult subject you have studied in college?
Suppose you know only java and they can ask questions like ‘Within the next one year artificial intelligence is only going to rule the world but you are saying that you only know Java’.
What is the latest technology you know?
Tell me about the subjects what you learnt in college these four years?

So you should be ready to answer these questions as you are going to work in an IT company where technologies and lot of advancements are coming each and every year. So you should always be in a position to update your knowledge then and there.

What is your area of interest?

This is also one of the questions asked in the Infosys Technical Interview. So depending on your area of interest, the questions may vary from person to person. You can say one or two areas of interest and make sure that whatever you have mentioned in the resume tell the same. Don’t say some random subjects. After this question, you will be questioned from your areas of interest. Answer them confidently. Suppose if you wrote DBMS as your area of interest then you should know all the concepts in DBMS. If you have given SQL then they may ask you to write SQL Queries or ask some theoretical questions like ” What is normalisation? Tell about the different normal forms present”.