Lumen Technologies Software Development Engineer Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions on OOPS and OS mainly.

Q1. What are Little Endian and Big Endian in the context of computer architecture?
Ans. 
Little Endian and Big Endian refer to the order in which bytes are stored in computer memory.
• Little Endian stores the least significant byte first, while Big Endian stores the most significant byte first.

• Little Endian is commonly used in x86 architecture, while Big Endian is used in architectures like SPARC and PowerPC.

• Endianness can affect data transmission between systems with different byte orders.
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Q2. Write a program to determine if your system is little-endian or big-endian.
Ans. 
Program to determine system's endianness
• Check the endianness by storing a multi-byte integer and checking the byte order

• Use bitwise operations to extract the least significant byte

• If the least significant byte is at the lowest memory address, it's little-endian

• If the least significant byte is at the highest memory address, it's big-endian
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Q3. What is the volatile keyword in programming?
Ans. 
The volatile keyword in programming is used to indicate that a variable's value can be changed unexpectedly.
• Volatile keyword is used in multithreaded programming to prevent compiler optimizations on variables that can be changed by other threads.

• It tells the compiler not to cache the variable's value in a register, ensuring that every access is made to the variable's memory location.

• Commonly used in embedded systems pr...read more
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Q4. What is the use of a function pointer in C?
Ans. 
Function pointers in C are used to store the address of functions, allowing for dynamic function calls and callbacks.
• Function pointers can be used to implement callbacks in event-driven programming.

• They can be used to switch between different functions at runtime.

• Function pointers are commonly used in implementing data structures like function pointers in an array of function pointers.

• Example: void (*funcPtr)(int) = &a
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Q5. Design a data structure to implement multi-threading.
Ans. 
Design a data structure for multi-threading
• Use a thread-safe queue to manage tasks for each thread

• Implement a lock or semaphore to control access to shared resources

• Consider using condition variables for synchronization

• Use atomic operations for shared variables to prevent race conditions
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Q6. What does a kernel do?
Ans. 
The kernel is the core component of an operating system that manages system resources and provides a bridge between software and hardware.
• Manages system resources such as CPU, memory, and I/O devices

• Provides a bridge between software applications and hardware components

• Handles tasks such as process scheduling, memory management, and device drivers

• Controls communication between hardware and software layers
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Q7. What is a storage class in programming?
Ans. 
A storage class in programming defines the scope and lifetime of variables.
• Storage classes include auto, register, static, and extern.

• Auto variables are created when a function is called and destroyed when the function ends.

• Register variables are stored in CPU registers for faster access.

• Static variables retain their value between function calls.

• Extern variables are declared outside of any function and can be accessed
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Round duration - 30 minutes
Round difficulty - Easy

HR round with typical behavioral problems.

Round duration - 40 minutes
Round difficulty - Easy

Technical round with questions based on DSA.

Q1. 
Reverse a Number Problem Statement
Create a program to reverse a given integer N. The output should be the reversed integer.
Note:
If a number has trailing zeros, their reversed version should not inclu...read more
Ans. 
Reverse a given integer while excluding trailing zeros.
• Create a program to reverse the given integer by converting it to a string and then reversing it.

• Remove any trailing zeros from the reversed string before converting it back to an integer.

• Handle the constraints of the input integer being between 0 and 10^8.

• Example: For input 1230, the output should be 321.
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Q2. 
Reverse a Linked List Problem Statement
You are given a Singly Linked List of integers. Your task is to reverse the Linked List by changing the links between nodes.
Input:
The first line of input contai...read more
Ans. 
Reverse a given singly linked list by changing the links between nodes.
• Iterate through the linked list and reverse the links between nodes.

• Use three pointers to keep track of the current, previous, and next nodes.

• Update the links while traversing the list to reverse it.

• Return the head of the reversed linked list.
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Q3. What is the difference in C++ between 'new int[5]' and 'malloc(5 * sizeof(int))'?
Ans. 
new int[5] is C++ specific and initializes the array with default values, while malloc(5 * sizeof(int)) is a C function and does not initialize the array.
• new int[5] is C++ specific and calls constructors for each element in the array.

• malloc(5 * sizeof(int)) is a C function and does not call constructors, leaving the array uninitialized.

• new int[5] returns a pointer to the first element of the array, while malloc(5 * siz...read more
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