Infosys Technical Interview Questions

By | October 6, 2021
Infosys Technical Interview Questions

Infosys is an Indian MNC that is among the most prominent IT players in the world. It could be a dream company for many Indian developers and an excellent platform to start your career in IT. Here in this article, we will discuss top Infosys technical interview questions.

Infosys Technical Interview Questions

Question No. 1: Name some high-level programming languages.


  • C++
  • C#
  • Java
  • Python
  • Go
  • Swift
  • PHP
  • JavaScript

Question No. 2:  C is sometimes considered a low-level programming language. Why so?

Answer: Though C mainly supports the concept of high-level programming language, it is sometimes considered a low-level programming language because it allows bit-orientated operation, direct memory access, and raw pointers.

Question No. 3:  What is a preprocessor in C?

Answer: The preprocessor is not a part of the compiler but a separate step at the time of compilation.  All those commands we write at the top of the program code that starts with a # symbol are preprocessors in C.

Question No. 4: Name basic OOPs concepts.

Answer: Following are the various OOPs concepts:

  • Abstraction
  • Encapsulation
  • Inheritance
  • Polymorphism

Question No. 5: What is inheritance? Name its types.

Answer: Inheritance is one of the important concepts of OOPs languages. With inheritance, we can apply the properties of one class to another class. The concept of inheritance increases the code reusability of the programming language.

Question No. 6: Please enumerate the various types of inheritance.


  • Single inheritance.
  • Multi-level inheritance.
  • Hierarchical inheritance.
  • Multiple inheritance.
  • Hybrid inheritance.
  • Multipath inheritance.

Question No. 7: What are tokens in C++?

Answer: Tokens are the smallest elements in C++ that make more sense to a compiler. Identifiers, keywords, literals, operators, punctuations, and other separators are examples of tokens.

Question No. 8: What is the difference between multi-level and multiple inheritance?

Answer: In multi-level inheritance, the derived class is derived from another derived class. Multiple inheritance, however, happens when a single class derives from multiple base classes.

Question No. 9: Give some differences between C++ and Java.


Parameters C++ Java
Platform dependency C++ is platform-dependent. It is platform-independent.
Usages It is mainly used for Windows software. Java is used to build applications for different platforms and web applications.
Multiple Inheritance C++ supports multiple inheritance. There is no support for multiple inheritance in Java. To achieve so, it has the concept of interfaces.
Pointer Provides supports for explicit pointer usage. Java does not support explicit pointers.

Question No. 10: How encapsulation and abstraction are complementary?

Answer: Both encapsulation and abstraction serve a similar purpose but in a distinct manner. Encapsulation is used to wrap the data in a single unit, such as class, whereas abstraction deals with hiding the data from the user in the form of class.

Question No. 11: What are arrays?

Answer: An array is the most important data structure, and every high-level programming language support it. Arrays are a collection of similar data types stored in a contiguous memory location. This makes array elements retrieval very efficient and fast.

Question No. 12: What is a pointer in C?

Answer: A pointer in C is a variable that stores the address of another variable. Also, the data type of the pointer variable and the variable it is storing should be the same. Pointers are basically used at the time of dynamic memory allocation.

Question No. 13: Give some differences between C and C++.


Parameters C++ C
Type It is a procedural as well as an object-oriented programming language. C is a procedural language.
Data security C++ follows the concept of OOPS, which increases data security. Data is less secure in C than C++.
Namespace C++ has the namespace feature. C does not have namespaces.
Exception handling It supports exception handling. There is no exception handling in C.

Question No. 14: What is a NULL pointer?

Answer: Pointers that points to no objects or variables are known as NULL pointers. A NULL pointer is mainly used to refer to the endpoint of any data structure, such as a list.

Question No. 15: Give logic to swap two numbers without using a temporary variable.


i = i + j;
j = i – j;
i= i – j;

Question No. 16: What is a virtual function?

Answer: Those functions which have a virtual keyword before their name in the base class and are redefined in the derived class are known as virtual functions.

Question No. 17: What is a pure virtual function?

Answer: A virtual function becomes a pure virtual function if it does not have any definition in the base class and its function declaration is set to 0.

Question No. 18: What is the difference between the process memory allocation and deallocation in Java and C++?

Answer: In C++, memory allocation and deallocation are done manually by the developer using the calloc(), malloc(), free() and new functions, while in Java, the interpreter takes care of the memory allocation and deallocation of the objects.

Question No. 19: What is a heap binary tree?

Answer: A binary heap is a complete binary tree that satisfies the heap ordering property, and it has two types:

  1. Min-heap property: In this, each child node has an equal or greater value than the parent node, and here the root node has the minimum value.
  2. Max heap property: Here, each child node has a less or equal value to the parent node, and here root node has the maximum value.

Question No. 20: What is a linked list?

Answer: It is a very popular data structure that is often compared with arrays. A linked list is a collection of homogenous or heterogeneous data elements that are stored at different memory locations.

Question No. 21: Give some difference between the linked list and array.


Parameters Linked-list Array
Size type It is dynamic in size. Arrays are fixed in size.
Data type It can store both homogeneous as well as heterogeneous data types. It can only store the same data types.
Speed A linked list is slow compared to an array. Data is stored at contiguous memory locations, which makes it faster.
Element Accessibility Random accessibility is not possible in a linked list. Random element accessibility is possible in an array with the help of indexing.
Memory efficient A linked-list is a more memory efficient data structure. Arrays are not memory efficient data structures.

Question No. 22: What do you mean by cross-platform?

Answer: A cross-platform system or software means that the product or system can work on different platforms or operating systems. These are also known as platform-independent systems.

Question No. 23: Give some differences between DOS and Windows.


Parameters DOS Windows
Multi-threading DOS is a single-tasking OS. Windows are designed to perform multiple tasks.
User interface DOS uses a plain interface, basically the console. Windows provide a graphical interface.
Operation It is not easy to operate DOS. You should have knowledge of each command. It is very easy to run Windows because of the graphical interface.
Features In DOS, we can play games and listen to music. Windows provide us with features like playing games and music.
Performance DOS is way faster than Windows. The speed of Windows is very slow.

Question No. 24: What is an RDBMS?

Answer: RDBMS stands for Relational Database Management System, and it is a subset of DBMS. RDBMS is the most efficient among database management systems because it stores data in the form of rows and columns.

Question No. 25: What is the difference between char and varchar in DBMS?


Char Varchar
It stores a character string with a fixed length. It also stores a character string but of variable length.
Char has a maximum limit of 255 characters. It has a character limit of 65,535 characters.
It is 50% faster than varchar. Varchar is slower than char.
Uses the static memory allocation technique. Use dynamic memory allocation.

Question No. 26: What is a database schema?

Answer: A schema of a database is a logical view of a complete database. The database schema represents the data organization and relation in a database, and it is used to define the database entity and relations between those entities.

Question No. 27: What is DSN?

Answer: Data Source Name (DSN) provides connectivity to a database through an ODBC driver. The DSN contains the database name, directory, database driver, UserID, password, and other information. Once you create a DSN for a particular database, you can use the DSN in an application to call information from the database.

Question No. 28: What is DNS?

Answer: DNS stands for Domain Name System, and it is like a phonebook of the Internet. Domain Name System is used to provide an alphanumeric name to the IP addresses registered on the server.

Question No. 29: What is Normalization in DBMS?

Answer: Normalization is a process or technique used on databases to reduce data redundancy and increase the dependency of data. It is basically used to divide a big table into small tables so the unwanted or repeated data can be removed.

Question No. 30: Differentiate between ‘a’ and “a.”

Answer: ‘a’ is a character literal, and it has a type char with value 97 on most systems.

“a” is a string literal, and its type is const char[2], and it refers to an array of size 2.


In this article, we have provided the top Infosys technical interview questions. After reading all the Infosys technical interview questions, you will notice that most of the questions are from C and C++, which also includes OOPs concept with data structure because these are the basis of programming languages, and a developer should have knowledge of basic technical stuff.

Also, C and C++ questions are easy to tackle if you have a degree in computer science, as you would have learned these two languages in your course curriculum. What Infosys technical interview questions you faced in your Infosys interview? Let us know via comments.

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