10+ NEXTracker Interview Questions and Answers

A stack is a data structure that follows Last-In-First-Out (LIFO) principle, while a queue follows First-In-First-Out (FIFO) principle. A linked list is a linear data structure where each element is a separate object with a pointer to the next element.

• Stack is like a stack of plates, where the last plate added is the first one to be removed. Example: undo-redo functionality in a text editor.

• Queue is like a queue of people waiting in line, where the first person added is the f...read more

Polymorphism is the ability of an object to take on many forms. It allows objects of different classes to be treated as the same type.

• Polymorphism is a fundamental concept in object-oriented programming.

• It enables code reusability and flexibility.

• Polymorphism can be achieved through method overriding and method overloading.

• Example: A parent class 'Animal' can have multiple child classes like 'Dog', 'Cat', etc. All these child classes can be treated as 'Animal' objects.

• Polymor...read more

OOPS examples in real life

• Inheritance: Children inheriting traits from parents

• Polymorphism: A person can be a student, teacher, or employee at different times

• Encapsulation: A car's engine is encapsulated and hidden from the user

• Abstraction: A TV remote has buttons that abstract the complex functions of the TV

• Interface: A USB port is an interface that allows different devices to connect

Operating systems (OS) are software that manage computer hardware and software resources. Different types include Symbian, Android, and Windows.

• Operating systems manage computer hardware and software resources

• Symbian is a discontinued mobile OS primarily used in Nokia smartphones

• Android is a popular mobile OS developed by Google

• Windows is a widely used OS for personal computers

The pollution control board acts as a regulatory body overseeing environmental protection and pollution prevention.

• Regulates and enforces laws related to pollution control

• Monitors and assesses pollution levels in air, water, and soil

• Issues permits for industries to ensure compliance with pollution standards

• Implements strategies for pollution prevention and environmental conservation

Forms authentication in MVC is implemented by configuring the web.config file and using the Authorize attribute in controllers.

• Configure forms authentication in web.config file

• Use Authorize attribute in controllers to restrict access to authenticated users

• Set authentication cookie upon successful login

The null coalescing operator (??) is used to provide a default value for nullable types if the value is null.

• Null coalescing operator (??) is used to return the left-hand operand if the operand is not null, otherwise it returns the right-hand operand.

• Example: int? x = null; int y = x ?? -1; // y will be -1 since x is null

• It is commonly used with nullable types to provide a default value if the nullable type is null.

Static middleware is used in web development to serve static files such as HTML, CSS, and images.

• Static middleware is a piece of Express.js middleware that serves static files from a specified directory.

• It is commonly used to serve files like HTML, CSS, images, and JavaScript.

• Static middleware can be added to an Express application using the 'express.static' method.

• Example: app.use(express.static('public')) will serve files from the 'public' directory.

ReactJS is a JavaScript library used for building user interfaces.

• ReactJS is a component-based library

• It uses a virtual DOM for efficient rendering

• It allows for reusable code through components

• ReactJS can be used for both web and mobile app development