20+ Cognizant Full Stack Software Developer Interview Questions and Answers

An array linked list can be executed using a loop to traverse through the array and access the linked nodes.

• Create an array to store the linked nodes

• Assign the first node to the first element of the array

• Use a loop to traverse through the array and access the linked nodes

• To access the next node, use the index of the current node as the index of the next node in the array

• Stop the loop when the last node is reached

Primary key uniquely identifies a record, foreign key links tables, candidate key can be primary key, super key is a set of attributes.

• Primary key: Unique identifier for a record in a table

• Foreign key: Links tables together by referencing the primary key of another table

• Candidate key: A set of attributes that can be used as a primary key

• Super key: A set of attributes that can uniquely identify a record

Streams in C++ are used for input and output operations. Predefined streams in C++ include cin, cout, cerr, and clog.

• Streams in C++ are objects that allow reading from or writing to external sources or destinations.

• cin is the standard input stream used for reading input from the user.

• cout is the standard output stream used for printing output to the console.

• cerr is the standard error stream used for printing error messages to the console.

• clog is an alternative to cerr for pri...read more

Reference variables in C++ are aliases for other variables, allowing direct access and manipulation of the original data.

• Reference variables are declared using an ampersand (&) symbol.

• They must be initialized when declared and cannot be reassigned to refer to a different variable.

• Changes made to a reference variable affect the original variable it refers to.

• They are commonly used to pass variables by reference to functions.

• Reference variables can be used to create multiple na...read more

Scope rules in C++ determine the visibility and accessibility of variables and functions within a program.

• Variables declared within a block have local scope and are only accessible within that block.

• Global variables have file scope and can be accessed from any function within the file.

• Function parameters have function scope and are only accessible within that function.

• Nested blocks can have their own scope, and variables declared within them are only accessible within that bl...read more

Semaphore and monitor are synchronization tools used in concurrent programming.

• Semaphore is a signaling mechanism that allows multiple threads to access a shared resource simultaneously.

• Monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait (block) for a certain condition to become true.

• Semaphore is a lower-level primitive, while monitor is a higher-level abstraction.

• Semaphore can be used to implement a monitor.

• Example...read more

BCNF is not necessarily better than 2NF & 3NF, it depends on the specific requirements of the database.

• BCNF is the highest normal form and ensures that there are no non-trivial functional dependencies between any subset of candidate keys.

• 2NF and 3NF are also important and should be used when appropriate.

• For example, if a database has a composite primary key and non-key attributes that depend on only one part of the key, 2NF should be used.

• If a database has transitive dependen...read more

Normalization is a process of organizing data in a database to eliminate redundancy and improve data integrity.

• First Normal Form (1NF) - Eliminate duplicate data by separating them into multiple tables.

• Second Normal Form (2NF) - Remove partial dependencies by creating separate tables for sets of attributes.

• Third Normal Form (3NF) - Eliminate transitive dependencies by creating separate tables for related attributes.

• Boyce-Codd Normal Form (BCNF) - Remove anomalies by ensuring ...read more

rand() generates a random number, srand() seeds the random number generator.

• rand() generates a pseudo-random number between 0 and RAND_MAX

• srand() sets the seed for the random number generator used by rand()

• srand() should be called before rand() to ensure different sequences of random numbers

• Example: srand(time(NULL)) sets the seed to the current time, ensuring a different sequence each time the program is run

Top-n analysis is a technique used in DBMS to retrieve the top n records based on a specific criteria.

• Used to retrieve top n records

• Based on specific criteria

• Commonly used in data analysis and reporting

Character constants are fixed values represented by a single character in C++.

• They are enclosed in single quotes (' ')

• Examples include 'a', 'B', '5', '$'

• They are also known as character literals

Normalisation is the process of organizing data in a database to reduce redundancy and improve data integrity.

• It involves breaking down a table into smaller tables and defining relationships between them.

• Normalization helps to eliminate data inconsistencies and anomalies.

• There are different levels of normalization, with each level having specific rules to follow.

• Examples of normalization include converting repeating groups into separate tables and creating a junction table fo...read more

INDEX is generally created on columns that are frequently used in WHERE, JOIN, and ORDER BY clauses.

• INDEX improves the performance of SELECT queries.

• INDEX should be created on columns with high selectivity.

• INDEX should not be created on columns with low selectivity.

• Examples of columns to create INDEX on are primary keys, foreign keys, and columns used in search queries.

Exclusive lock is used when a resource is being modified and prevents other processes from accessing it. Shared lock allows multiple processes to read a resource simultaneously.

• Exclusive lock is used for write operations, while shared lock is used for read operations.

• Exclusive lock blocks other processes from acquiring both exclusive and shared locks on the same resource.

• Shared lock allows multiple processes to acquire shared locks on the same resource simultaneously.

• Exclusiv...read more

Linked List is a linear data structure. Stack and Queue are abstract data types.

• Linked List: A collection of nodes where each node points to the next node.

• Stack: A data structure where elements are added and removed from the top only.

• Queue: A data structure where elements are added at the rear and removed from the front only.

• Example: Browser history can be implemented using a Linked List.

• Example: Undo/Redo functionality can be implemented using a Stack.

• Example: Print queue ca...read more

Object oriented model is a programming paradigm that uses objects to represent real-world entities.

• Objects have properties and methods that define their behavior

• Encapsulation, inheritance, and polymorphism are key concepts in OOP

• Examples of OOP languages include Java, C++, and Python

OSI, TCP & IP are networking protocols used for communication between devices on a network.

• OSI (Open Systems Interconnection) is a conceptual model that defines how data is transmitted over a network.

• TCP (Transmission Control Protocol) is a protocol that ensures reliable transmission of data between devices.

• IP (Internet Protocol) is a protocol that handles the addressing and routing of data packets between devices on a network.

• TCP/IP is a suite of protocols that are commonly ...read more

An operating system is a software that manages computer hardware and software resources.

• It acts as an interface between the user and the computer hardware.

• It provides services to applications and manages system resources.

• Examples include Windows, macOS, Linux, Android, and iOS.

RDBMS KERNEL is not a commonly used term in the industry.

• There is no widely accepted definition of RDBMS KERNEL.

• It may refer to the core components of a relational database management system.

• It could also be a term used by a specific company or product.

• Without more context, it is difficult to provide a specific answer.

Triggers are events that initiate an action or set of actions. They are commonly used in databases and automation systems.

• Triggers are used in databases to automatically execute a set of actions when a certain event occurs, such as inserting or updating data.

• They can also be used in automation systems to initiate a process or workflow when a specific event occurs, such as receiving an email or a file upload.

• Triggers can be programmed to perform a variety of actions, such as s...read more

DML is provided to manipulate data in a database.

• DML stands for Data Manipulation Language.

• It is used to insert, update, delete, and retrieve data from a database.

• DML commands include INSERT, UPDATE, DELETE, and SELECT.

• DML is essential for managing and maintaining data in a database.

Promise is a one-time event while Observable can emit multiple values over time.

• Promise is used for asynchronous operations that will return a single value or an error.

• Observable is used for asynchronous operations that can return multiple values over time.

• Promise can be in one of three states: pending, fulfilled, or rejected.

• Observable can emit values, errors, and completion events.

• Promise can be converted to an Observable using the from() method in RxJS.

• Observable can be co...read more

RDBMS is a type of DBMS that stores data in a structured manner using tables with relationships.

• RDBMS stands for Relational Database Management System

• Data is stored in tables with predefined relationships

• Data is accessed using SQL (Structured Query Language)

• Examples include MySQL, Oracle, and SQL Server

• DBMS is a broader term that includes all types of database management systems

• Examples of DBMS include MongoDB, Cassandra, and Redis

Jwt security implementation in Angular

• Install angular-jwt package

• Create an auth service to handle token storage and retrieval

• Add an HttpInterceptor to attach the token to outgoing requests

• Use guards to protect routes based on authentication status

Transparent DBMS allows users to see and control the underlying database operations.

• Transparent DBMS provides visibility into the database operations and allows users to monitor and control them.

• It enables users to see how data is being stored, accessed, and manipulated in real-time.

• Examples include Oracle Transparent Data Encryption and Microsoft SQL Server Transparent Data Encryption.

• Transparent DBMS can improve security, performance, and compliance with regulations.

RDBMS stands for Relational Database Management System.

• It is a type of database management system that stores data in tables with relationships between them.

• It uses SQL (Structured Query Language) to manipulate and retrieve data.

• Examples include MySQL, Oracle, and Microsoft SQL Server.

A subquery is a query within another query used to retrieve data that will be used in the main query.

• Subqueries are enclosed in parentheses and placed within the WHERE clause of the main query.

• They can be used to filter results based on a condition that involves data from another table.

• Subqueries can also be used in the SELECT, FROM, and HAVING clauses.

• Examples include finding the average salary of employees in a department or selecting the top 5 customers based on their tota...read more