Lumen Technologies Network Engineer Interview Questions and Answers

Program to reverse an integer

• Convert the integer to a string

• Reverse the string

• Convert the reversed string back to an integer

I have worked on various projects including a web application for inventory management and a mobile app for task tracking.

• Developed a web application using React for inventory management, allowing users to track stock levels and generate reports.

• Created a mobile app using Flutter for task tracking, enabling users to create, assign, and track tasks in real-time.

• Collaborated with a team of developers to integrate APIs an...read more

Data structures are fundamental concepts in software engineering that organize and store data efficiently.

• Arrays: Simple and efficient for storing and accessing elements.

• Linked Lists: Dynamic and flexible, efficient for insertion and deletion.

• Stacks: LIFO structure, useful for managing function calls and undo operations.

• Queues: FIFO structure, ideal for managing tasks and scheduling.

• Trees: Hierarchical structure, used ...read more

The difference is that 'int arr[5]' creates an array on the stack, while 'malloc(5*sizeof(int))' allocates memory on the heap.

• int arr[5] creates an array of 5 integers on the stack, which is a fixed-size memory allocation.

• malloc(5*sizeof(int)) dynamically allocates memory on the heap, allowing for variable-size memory allocation.

• The memory allocated with malloc must be explicitly freed with free() to avoid memory leaks...read more

MAC addresses are required for identifying devices on a local network, while IP addresses are used for identifying devices on a global network.

• MAC addresses are used for communication within a local network

• IP addresses are used for communication across different networks

• MAC addresses are assigned by the manufacturer and cannot be changed

• IP addresses can be assigned dynamically or statically

• MAC addresses are used in the...read more

An ArrayList is a dynamic array in Java that can grow or shrink in size during runtime.

• ArrayList is a class in Java's Collection framework.

• It implements the List interface and allows duplicate elements.

• Elements can be added or removed using methods like add(), remove(), etc.

• It can also be sorted using the sort() method.

• Example: ArrayList names = new ArrayList<>();

• names.add("John"); names.add("Mary"); names.remove(0);

Java is not a pure OO language due to primitive types not being objects.

• Primitive types like int, boolean, etc. are not objects in Java

• They do not have methods or inheritance like objects do

• This violates the principle of everything being an object in pure OO languages

• Wrapper classes like Integer, Boolean, etc. were introduced to provide object-like behavior for primitives

Inheritance is a way to create new classes based on existing ones. Abstraction is a way to hide implementation details.

• Inheritance allows a subclass to inherit properties and methods from a superclass.

• Abstraction allows a class to provide a simplified interface to its users while hiding its implementation details.

• For example, a Car class can inherit properties and methods from a Vehicle class, while also implementing i...read more