91mobiles.com Interview Questions and Answers

Find the first non-repeating character in a string.

• Create a hash table to store the frequency of each character in the string.

• Iterate through the string and check the frequency of each character.

• Return the first character with a frequency of 1.

Connection pooling is a technique of reusing database connections to improve performance.

• Connection pooling helps to reduce the overhead of creating and destroying database connections.

• It maintains a pool of connections that can be reused by multiple clients.

• Connection pooling is commonly used in web applications to handle multiple requests simultaneously.

• It can be configured with parameters like maximum number of conn...read more

A singleton class in PHP is a class that can only be instantiated once.

• Create a private constructor to prevent direct instantiation

• Create a private static variable to hold the instance of the class

• Create a public static method to get the instance of the class

• Ensure that the public static method always returns the same instance

To connect to MySQL database using PHP, create a Connection class.

• Use mysqli_connect() function to establish a connection

• Pass the database credentials as parameters to the function

• Create a constructor method to initialize the connection

• Create a query method to execute SQL queries

• Close the connection using mysqli_close() method

There are three types of errors in PHP: syntax errors, runtime errors, and logical errors.

• Syntax errors occur when the code is not written correctly, such as missing semicolons or parentheses.

• Runtime errors occur during the execution of the code, such as trying to access an undefined variable.

• Logical errors occur when the code runs without errors, but produces unexpected results, such as a miscalculation in a formula.

Session in PHP allows to store user data on the server for later use.

• Session starts when a user logs in and ends when the user logs out or the session expires.

• Session data is stored on the server and identified by a unique session ID.

• Session variables can be set and accessed using the $_SESSION superglobal array.

• Session can be destroyed using the session_destroy() function.

• Session can be used to store user-specific dat...read more

Find missing element in an array of elements from 0 to n-1

• Calculate sum of all elements in array and subtract from sum of n natural numbers

• Use XOR operation on all elements and n natural numbers

• Sort the array and find the missing element

During my summer training, I learned various programming languages, software development methodologies, and practical application of theoretical concepts.

• Learned programming languages such as Java, Python, and SQL

• Gained knowledge of software development methodologies like Agile and Waterfall

• Applied theoretical concepts in real-world projects, enhancing problem-solving skills

In 5 years, I see myself as a senior software engineer leading a team of developers on innovative projects.

• Continuing to enhance my technical skills through ongoing learning and certifications

• Taking on more leadership responsibilities within the team

• Contributing to the company's growth and success through my expertise

• Mentoring junior team members to help them grow in their careers

I am a results-driven sales professional with 5+ years of experience in exceeding sales targets and building strong client relationships.

• Experienced in B2B sales and account management

• Proven track record of meeting and exceeding sales targets

• Strong communication and negotiation skills

• Ability to build and maintain strong client relationships

• Proficient in CRM software and sales analytics

Customer service refers to the assistance and support provided to customers before, during, and after a purchase.

• Customer service involves addressing customer inquiries, concerns, and complaints.

• It includes providing information about products or services, helping customers make purchasing decisions, and resolving issues.

• Customer service can be provided through various channels such as phone, email, live chat, or in-pe...read more

To sell our product, we need to understand the customer's needs and show them how our product can solve their problems.

• Research and understand the target market

• Identify the customer's pain points and needs

• Highlight the unique features and benefits of our product

• Provide excellent customer service and follow-up

• Offer promotions or discounts to incentivize purchase

• Use persuasive language and storytelling to create an emoti...read more

As a Senior Software Engineer, I worked with various tools and technologies to develop and maintain software applications.

• Developed and maintained software applications using Java, Python, and C++ programming languages

• Used Agile methodology for software development and collaborated with cross-functional teams

• Worked with various tools such as Git, JIRA, Jenkins, and Docker for version control, issue tracking, continuous...read more

Firmware is a type of software that is embedded in hardware devices to control their functionality.

• Firmware is a combination of hardware and software.

• It is used to control the behavior of hardware devices.

• Firmware is typically stored in non-volatile memory, such as ROM or flash memory.

• Examples of devices that use firmware include routers, printers, and digital cameras.

I am a passionate software developer with experience in building web applications and solving complex problems.

• Experienced in programming languages such as Java, JavaScript, and Python

• Familiar with front-end technologies like HTML, CSS, and React

• Strong problem-solving skills and ability to work in a team environment

• Previous projects include developing a customer management system for a small business