HCLTech Interview Questions and Answers

20 - MCQ test related C&C++ basic to advance
2 - coding questions -
1) create class which allows only one instance creation at a time if you try to create another before deleting existing object then class should throw exception..

2) find the distance between leftmost string and rightmost string(string's chars order doesn't matter) In a given long shuffled string.
Ex :-
Shuffled string = "xaxxcxbxxxcxxaxxbx"
target string= "abc"
Ans: 3
(Leftmost string is last index 6
Right most is 9 so 9-6=3)
Note:- other chars not necessarily 'x' it can be any

Q1. Explain oops concepts
Ans. 
OOP is a programming paradigm based on the concept of objects, which can contain data and code to manipulate that data.
• OOP focuses on creating objects that interact with each other to solve complex problems.

• Encapsulation: Objects encapsulate data and behavior within a single unit.

• Inheritance: Objects can inherit attributes and methods from other objects.

• Polymorphism: Objects can take on different forms or have multiple...read more
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Q2. Runtime polymorphism with example
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Runtime polymorphism allows objects of different classes to be treated as objects of a common superclass.
• Use virtual functions in base class and override them in derived classes

• Use pointers or references of base class to call derived class methods

• Example: Animal class with virtual function 'makeSound', Dog and Cat classes overriding 'makeSound'
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Q3. Vtable and Vptr working
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Q4. Abstraction and pure virtual function
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Q5. Smart pointers
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Q6. Implementation of STL libraries any container class ex:- Vector
Ans. 
STL libraries provide efficient and easy-to-use container classes like Vector for storing and manipulating data.
• STL Vector is a dynamic array that can resize itself automatically.

• It provides random access to elements, similar to arrays.

• Vector supports various operations like push_back, pop_back, insert, erase, etc.

• Example: std::vector<int> numbers = {1, 2, 3, 4, 5};
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Q7. Singleton class creation (code) what is use of it ?
Ans. 
Singleton class ensures only one instance of a class is created and provides a global point of access to it.
• Ensures only one instance of a class is created

• Provides a global point of access to the instance

• Useful for managing global resources or settings
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Q8. SQL simple questions
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Q9. What is the use of Mutex
Ans. 
Mutex is used in multithreading to prevent multiple threads from accessing shared resources simultaneously.
• Mutex stands for mutual exclusion and is used to synchronize access to shared resources in multithreaded programs.

• It allows only one thread to access the shared resource at a time, preventing data corruption or race conditions.

• Mutexes are typically used in critical sections of code where data integrity is importan...read more
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Q10. Be strong in theoretically (why, what when to use the concept)
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Q1. Tell me about your self
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Q2. About your current role and responsibilities
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Q1. About your technical skills
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Q1. Salary negotiation
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Q1. What tools are you using, and what types of applications are you supporting?
Ans. 
I use tools like remote desktop software, ticketing systems, and knowledge bases to support various applications such as Microsoft Office, antivirus software, and VPN clients.
• Remote desktop software (e.g. TeamViewer, AnyDesk)

• Ticketing systems (e.g. ServiceNow, Jira)

• Knowledge bases (e.g. Confluence, SharePoint)

• Applications like Microsoft Office, antivirus software, VPN clients
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Q2. What is mean by ITSM , incident management and service request difference, Change management
Ans. 
ITSM stands for Information Technology Service Management. Incident management deals with resolving unplanned interruptions to services. Service request management handles planned service requests. Change management involves controlling changes to IT systems.
• ITSM is a framework that helps organizations manage their IT services efficiently.

• Incident management focuses on restoring normal service operation as quickly as p...read more
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Q3. How do you handle critical operational issues?
Ans. 
I prioritize and escalate critical operational issues to ensure timely resolution and minimal impact on operations.
• Quickly assess the severity and impact of the issue

• Communicate with relevant stakeholders to gather information and coordinate response

• Follow established protocols and procedures for handling critical incidents

• Escalate to higher levels of support or management as needed

• Provide regular updates on the status...read more
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Q4. Can you please explain what kind of issues you are handling
Ans. 
I handle a variety of technical issues related to software, hardware, network connectivity, and user account access.
• Troubleshooting software applications for errors or bugs

• Resolving hardware malfunctions or issues

• Assisting with network connectivity problems

• Resetting passwords and troubleshooting user account access

• Providing technical support for various IT systems and tools
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Q5. What is the difference between Average Handling Time (AHT) and After Call Work (ACW), and what is your First Call Resolution (FCR) score?
Ans. 
AHT is the total time spent on a call including ACW, while ACW is the time spent after the call ends. FCR is the percentage of calls resolved on the first attempt.
• AHT includes the time spent talking to the customer and the time spent on ACW, while ACW is the time spent after the call ends for wrap-up tasks.

• For example, if a call lasts 10 minutes and the ACW is 2 minutes, the AHT would be 12 minutes.

• FCR is the percentag...read more
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Q6. How will the prioritization of tickets be managed before the Service Level Agreement (SLA)?
Ans. 
Tickets are prioritized based on impact, urgency, and customer importance before SLA.
• Tickets are categorized based on impact, urgency, and customer importance.

• High impact issues with urgent resolution needs are given top priority.

• Customer importance may also play a role in prioritization.

• Regular reviews and updates are done to ensure tickets are prioritized correctly.

• Automated ticketing systems may help in prioritizing...read more
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Q1. What is your Understanding of Design control process and what are PLM you have used.
Ans. 
Design control process ensures products meet requirements. PLM tools manage product data.
• Design control process ensures products meet design requirements and regulatory standards

• PLM tools (Product Lifecycle Management) are used to manage product data, documents, and processes

• Examples of PLM tools include Teamcenter, Windchill, and Agile PLM
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Q2. Share your knowledge in writing a protocol and procedure for medical devices.
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Q3. What is NPD(New product development)
Ans. 
NPD is the process of bringing a new product to market from concept to launch.
• NPD involves idea generation, product design, development, testing, and commercialization.

• It requires cross-functional collaboration between engineering, marketing, and other departments.

• Examples include Apple launching a new iPhone model or Tesla introducing a new electric car.
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Q4. Share experience on lab testing methods, material, procedure etc.. of Ethicon Sutures and needle .
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Q5. What is accelerated ageing process in storage chamber of suture testing lab.
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Q6. What about complaint handling process in BD (Becton Dickinson).
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Q1. Difference between keys and indexes in sql
Ans. 
Keys uniquely identify records, while indexes improve query performance by speeding up data retrieval.
• A primary key is a unique identifier for a record in a table, e.g., 'user_id' in a 'users' table.

• A foreign key establishes a relationship between two tables, e.g., 'order_id' in 'orders' referencing 'user_id' in 'users'.

• Indexes are data structures that improve the speed of data retrieval operations on a database table,...read more
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Q2. Is keys creates a index ?
Ans. 
Keys in SQL create indexes to enhance data retrieval speed and enforce uniqueness in tables.
• Primary Key: Automatically creates a unique index on the column(s) defined as the primary key, ensuring no duplicate values. Example: `PRIMARY KEY (id)`.

• Foreign Key: May create an index to improve join performance between tables. Example: `FOREIGN KEY (user_id) REFERENCES users(id)`.

• Unique Key: Creates a unique index to enforce ...read more
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Q3. What r the types of index and keys?
Ans. 
Indexes and keys are essential database structures that enhance data retrieval and enforce data integrity.
• Primary Key: Uniquely identifies each record in a table. Example: 'user_id' in a 'users' table.

• Foreign Key: Establishes a relationship between two tables. Example: 'user_id' in 'orders' table referencing 'users'.

• Unique Key: Ensures all values in a column are unique. Example: 'email' in a 'users' table.

• Composite Key...read more
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Q4. Difference between identity and sequenceNo with more details?
Ans. 
Identity columns auto-generate values for new rows, while sequences are independent objects for generating unique numbers.
• Identity: Automatically generates a unique value for each new row in a table.

• Example: In SQL Server, you can define a column as 'IDENTITY(1,1)' to start at 1 and increment by 1.

• Sequence: A separate database object that generates a sequence of numeric values.

• Example: In Oracle, you can create a seque...read more
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Q5. Difference between truncate and drop with more details. eg: 'A' table have a identity column with 10 rows. if I tried to delete or truncate a 2nd row, then what will be next value of identity column? (Plea...read more
Ans. 
Truncate removes all rows and resets identity, while delete removes specific rows without resetting identity.
• TRUNCATE TABLE removes all rows from a table and resets any identity columns to their seed value.

• DELETE FROM table_name removes specific rows based on a condition but does not reset identity columns.

• Example: If 'A' table has 10 rows with an identity column starting at 1, truncating will reset the next identity v...read more
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Q6. What is compile and recompile in sql?
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Compilation in SQL refers to the process of converting SQL code into an executable form, while recompilation occurs when changes are made.
• Compilation occurs when a SQL statement is first executed, creating an execution plan.

• Recompilation happens when the underlying data or schema changes, requiring a new execution plan.

• Example of recompilation: Changing a table structure (e.g., adding a column) may trigger recompilatio...read more
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Q7. What is execution plan?
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An execution plan is a roadmap that outlines how a SQL query will be executed by the database engine.
• It shows the steps the database will take to execute a query, including joins, scans, and sorts.

• Execution plans can be visualized using tools like SQL Server Management Studio or EXPLAIN in PostgreSQL.

• They help identify performance bottlenecks by showing which operations are most costly.

• Example: A query that joins two t...read more
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Q8. Uses of storeprocedures? (Eg: Execution plan use)
Ans. 
Stored procedures are precompiled SQL statements that enhance performance, security, and maintainability in database operations.
• Performance Optimization: Stored procedures are precompiled, which means the execution plan is cached, reducing the overhead of query parsing and optimization.

• Code Reusability: They allow developers to encapsulate complex logic in a single procedure, which can be reused across multiple applica...read more
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Q9. Sql server architecture basic?
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Q10. Can we crud operation inside a function or view?
Ans. 
CRUD operations are not allowed inside functions or views in SQL due to side effects and consistency issues.
• Functions in SQL are meant to return values and cannot perform data modification (INSERT, UPDATE, DELETE).

• Views are virtual tables and are used to present data; they do not support direct data manipulation.

• Using a function to perform CRUD can lead to unpredictable results and violate the principle of function pur...read more
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Q11. Can we call a procedure from a function?
Ans. 
A function cannot directly call a procedure in SQL due to restrictions on side effects and transaction control.
• Functions are designed to return a value and cannot perform actions that modify database state, such as calling procedures.

• Procedures can be called from other procedures or anonymous blocks, but not from functions due to their side effects.

• Example: If you have a procedure that updates a table, calling it from ...read more
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Q12. Difference between table variable and temp table with example?
Ans. 
Table variables and temp tables differ in scope, performance, and usage in SQL Server.
• Scope: Table variables are scoped to the batch, while temp tables are scoped to the session.

• Performance: Table variables are generally faster for small datasets, while temp tables can handle larger datasets better.

• Transaction Logging: Table variables have minimal logging, while temp tables are fully logged.

• Example of Table Variable: D...read more
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Q13. Query writing with joins and group by with having clause , where clause?
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Understanding SQL joins, group by, having, and where clauses for effective data querying.
• Joins combine rows from two or more tables based on a related column. Example: SELECT * FROM table1 JOIN table2 ON table1.id = table2.id;

• GROUP BY aggregates data across specified columns. Example: SELECT department, COUNT(*) FROM employees GROUP BY department;

• HAVING filters groups created by GROUP BY. Example: SELECT department, CO...read more
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Q14. Difference between where clause and having clause
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The WHERE clause filters rows before aggregation, while HAVING filters after aggregation in SQL queries.
• WHERE clause is used to filter records before any groupings are made.

• HAVING clause is used to filter records after aggregation functions like COUNT, SUM, AVG.

• Example of WHERE: SELECT * FROM employees WHERE salary > 50000;

• Example of HAVING: SELECT department, COUNT(*) FROM employees GROUP BY department HAVING COUNT...read more
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Q15. Type of functions and detailed explanation
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SQL functions are categorized into scalar, aggregate, and window functions, each serving distinct purposes in data manipulation.
• Scalar Functions: Operate on a single value and return a single value. Example: UPPER('abc') returns 'ABC'.

• Aggregate Functions: Operate on a set of values and return a single summary value. Example: COUNT(*) counts the number of rows.

• Window Functions: Perform calculations across a set of table...read more
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Q16. What is cursors? Create a cursor ( just to check whether u know write a cursor query) Alternate way to create a cursor(Answer is while loop)
Ans. 
Cursors are database objects used to retrieve, manipulate, and navigate through a result set row by row.
• Cursors allow for row-by-row processing of SQL results.

• Types of cursors: implicit and explicit.

• Example of creating an explicit cursor: DECLARE cursor_name CURSOR FOR SELECT column_name FROM table_name;

• To fetch data from a cursor: FETCH cursor_name INTO variable_name;

• An alternate way to process rows is using a WHILE...read more
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Q1. There were mainly 5 rounds : 1) Aptitude + Technical test 2) Group Discussion 3) Technical Interview 4) Business HR round 5) Campus HR round
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Q2. Difference between linear search and binary search 3) SQL queries involving - insert , update , sql joins 4) Project related : My project was based on ReactJs , so there was questions on ReactJs like Hooks...read more
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Q3. SQL queries involving insert , update , sql joins
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Q4. Project related : My project was based on ReactJs , so there was questions on ReactJs like Hooks , functional and class components
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Q5. JS - Difference between var , let and const.
Ans. 
var, let, and const are JavaScript keywords for variable declaration with different scopes and mutability.
• var: Function-scoped or globally scoped; can be re-declared and updated.

• Example: var x = 10; x = 20; // valid

• let: Block-scoped; can be updated but not re-declared in the same scope.

• Example: let y = 10; y = 20; // valid, let y = 30; // invalid in the same block

• const: Block-scoped; cannot be updated or re-declared; m...read more
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Q6. JS - Arrow functions , async and await
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Q7. If tailwind CSS is mentioned in your resume then - Difference between Tailwind CSS and normal CSS and how Tailwind CSS is better ?
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Q8. Merge Sort and other sorting algorithms
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Q9. Difference between merge sort and binary search
Ans. 
Merge sort is a sorting algorithm, while binary search is a searching algorithm used on sorted arrays.
• Merge Sort: A divide-and-conquer algorithm that sorts an array by dividing it into halves, sorting each half, and merging them back together.

• Example of Merge Sort: Sorting the array [38, 27, 43, 3, 9, 82, 10] results in [3, 9, 10, 27, 38, 43, 82].

• Binary Search: An efficient algorithm for finding an item in a sorted arr...read more
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