60+ Interview Questions and Answers

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.

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 for organizing data like file systems or search algorithms...read more

Swapping two particular bits of an integer program.

• Use bitwise operators to get the values of the two bits to be swapped

• Use XOR operator to swap the bits

• Shift the bits back to their original positions

• Example: Swapping 2nd and 5th bits of 8 (1000) gives 32 (100000)

• Example code: num ^= (1 << bit1) | (1 << bit2);

Reverse a linked list without using extra memory

• Iterate through the linked list and change the next pointers to reverse the list

• Use three pointers - prev, current, and next - to keep track of the reversed list

• Start with prev and current pointing to null and the head of the linked list respectively

• While traversing the list, update the next pointer of the current node to point to the previous node

• Move prev and current pointers one step forward

• Repeat until the end of the list is...read more

Find elements in array that sum up to given number

• Use a nested loop to iterate through each pair of elements in the array

• Check if the sum of the pair equals the given number

• Return the pair of elements if found, otherwise continue iterating

Program to reverse an integer

• Convert the integer to a string

• Reverse the string

• Convert the reversed string back to an integer

The automation framework I worked on improved efficiency and productivity in the business unit.

• The automation framework reduced manual effort by automating repetitive tasks.

• It improved the accuracy and reliability of the software development process.

• The framework enabled faster testing and deployment of software updates.

• It facilitated better collaboration and communication among team members.

• The automation framework helped in identifying and fixing bugs or issues more efficie...read more

IP packet header fields and their usage

• Version: indicates the IP version being used (IPv4 or IPv6)

• Header Length: specifies the length of the IP header

• Type of Service: used to prioritize packets

• Total Length: specifies the total length of the IP packet

• Identification: used to identify fragments of a larger packet

• Flags: used to control fragmentation

• Fragment Offset: used to reassemble fragmented packets

• Time to Live: specifies the maximum number of hops a packet can take

• Protocol: s...read more

TCP packet header fields and their usage

• TCP packet header consists of 20 bytes

• Fields include source and destination ports, sequence and acknowledgement numbers, flags, window size, and checksum

• Source and destination ports identify the endpoints of the connection

• Sequence and acknowledgement numbers are used for reliable data transfer

• Flags indicate the purpose of the packet, such as SYN, ACK, FIN, RST

• Window size is used for flow control

• Checksum is used for error detection

IPC mechanisms are used for inter-process communication in software development.

• IPC mechanisms allow processes to communicate with each other, either on the same machine or across a network.

• Common IPC mechanisms include pipes, message queues, shared memory, sockets, and signals.

• Examples of IPC mechanisms include using sockets for network communication between client and server applications, or using shared memory for communication between processes on the same machine.

Security is important in a system to protect against unauthorized access, data breaches, and cyber attacks.

• Prevents unauthorized access to sensitive data

• Protects against data breaches and cyber attacks

• Ensures confidentiality, integrity, and availability of data

• Compliance with regulations and standards

• Maintains trust and confidence of customers and stakeholders

TCP/IP is a protocol used for communication between devices on a network. TCP header contains information about the data being transmitted.

• TCP/IP is a suite of protocols used for communication between devices on a network

• TCP is a connection-oriented protocol that ensures reliable delivery of data

• IP is a connectionless protocol that handles the routing of data packets

• TCP header contains information such as source and destination ports, sequence and acknowledgement numbers, and...read more

VLAN is a logical network created by grouping devices together based on their functions or departments.

• VLAN stands for Virtual Local Area Network

• It allows multiple networks to coexist on the same physical network

• VLANs are created by assigning a group of devices to a specific VLAN ID

• VLAN header contains a 4-byte tag that identifies the VLAN ID

• VLAN header is added to the Ethernet frame before transmission

Socket communication is a method of communication between two processes on a network using sockets.

• Socket communication involves a client and a server communicating over a network.

• It uses TCP or UDP protocols to establish a connection.

• Data is exchanged through sockets using read and write operations.

• Sockets can be used for various applications like web browsing, email, and file transfer.

I2C and SPI are serial communication protocols used for connecting microcontrollers to peripherals.

• I2C (Inter-Integrated Circuit) is a synchronous, multi-master, multi-slave, packet-switched protocol commonly used for communication between integrated circuits.

• SPI (Serial Peripheral Interface) is a synchronous, full-duplex, master-slave communication protocol commonly used for communication between microcontrollers and peripheral devices.

• I2C uses two wires (SDA and SCL) for co...read more

Method overloading is creating multiple methods with the same name but different parameters. Method overriding is creating a new implementation of an existing method in a subclass.

• Method overloading is used to provide different ways of calling the same method with different parameters.

• Method overriding is used to change the behavior of an existing method in a subclass.

• Method overloading is resolved at compile-time based on the number and type of arguments passed to the method...read more

Asymmetric routing in a network can lead to issues such as packet loss, out-of-order delivery, and inefficient use of network resources.

• Packet loss: When packets take different paths to reach their destination, some packets may get lost or dropped along the way.

• Out-of-order delivery: Asymmetric routing can cause packets to arrive at the destination out of order, leading to delays in data transmission.

• Inefficient use of network resources: Asymmetric routing can result in subop...read more

Implement a shopping cart system using data structures and algorithms.

• Use a data structure like a hash map to store items and their quantities in the cart.

• Implement functions to add, remove, and update items in the cart.

• Consider implementing functions to calculate total price, apply discounts, and handle checkout process.

Blackhole issues with firewalls can cause slowness in forwarding traffic via MPLS and returning traffic via internet.

• Check firewall configurations to ensure proper routing of traffic

• Investigate blackhole issues to identify any dropped packets

• Consider implementing Quality of Service (QoS) policies to prioritize MPLS traffic

• Monitor network performance to detect any bottlenecks causing slowness

Implement a telephone directory program using an array of strings.

• Create an array of strings to store the directory

• Implement functions to add, delete, and search for entries

• Consider using a hash table for faster search times

• Include error handling for invalid input

Printing a tree in level order

• Use a queue to store nodes in level order

• Enqueue root node and print its value

• Dequeue the node and enqueue its children

• Repeat until queue is empty

Asymmetric routing occurs when data packets take different paths to reach their destination, leading to potential issues such as packet loss or out-of-order delivery.

• Asymmetric routing can occur in networks with multiple paths between source and destination.

• Issues with asymmetric routing include packet loss, out-of-order delivery, and potential security vulnerabilities.

• Examples of solutions to mitigate asymmetric routing issues include implementing symmetric routing policies ...read more

Binary search is a search algorithm that finds the position of a target value within a sorted array.

• Divide the array into two halves and compare the target value with the middle element.

• If the target value is equal to the middle element, return the index.

• If the target value is less than the middle element, recursively search the left half.

• If the target value is greater than the middle element, recursively search the right half.

Implement a custom hashmap in Java

• Create a class to represent the hashmap

• Use an array to store the key-value pairs

• Implement methods for put, get, and remove operations

Find the number of subarrays whose sum is divisible by K.

• Use prefix sum technique to calculate the sum of subarrays efficiently.

• Keep track of the remainders of prefix sums when divided by K.

• Use a hashmap to store the count of each remainder.

• For each prefix sum, check how many previous prefix sums have the same remainder.

• Add the count of subarrays with the same remainder to the total count.

Yes, we can overload the constructor in Java.

• Overloading constructor means creating multiple constructors with different parameters.

• The constructors can have different number of parameters or different types of parameters.

• The constructor with the matching parameters will be called during object creation.

Writing code on notepad instead of an IDE

• Ensure proper indentation and formatting

• Use comments to explain code

• Compile and test code manually

• Save frequently to avoid losing work

The program checks if a given string is a palindrome or not.

• Create a function that takes a string as input

• Reverse the string and compare it with the original string

• Return true if they are the same, false otherwise

Python uses dynamic typing to handle multiple object types, allowing variables to change types during runtime.

• Python uses dynamic typing, meaning variables can hold different types of objects at different times.

• Python does not require explicit declaration of variable types, allowing for flexibility in handling multiple object types.

• Python supports polymorphism, allowing objects of different types to be treated as instances of a common superclass.

• Python uses duck typing, focus...read more

When you cast a Python variable, you are converting its data type to a different type.

• Casting is the process of changing a variable's data type.

• For example, casting a string to an integer: x = '10' -> int(x) = 10

• Casting can result in data loss if the conversion is not possible or accurate.

A program to implement a dictionary using an array of strings.

• Use an array of strings to store the words and their definitions.

• Implement functions to add, delete, and search for words.

• Consider using a hash table for faster search times.

Reorder a linked list by alternating between the first and last elements

• Create two pointers, one at the beginning and one at the end of the linked list

• Iterate through the linked list, moving the first pointer to the next node and the second pointer to the previous node

• Adjust the pointers to reorder the linked list by alternating between the first and last elements

Arrays are a collection of strings in programming used to store multiple values under a single variable name.

• Arrays are declared using square brackets []

• Each element in an array is accessed by its index, starting from 0

• Example: var fruits = ['apple', 'banana', 'orange']

Trees in neet code refer to the implementation of tree data structures in coding challenges on the platform NeetCode.

• Trees are a common data structure used in coding challenges to represent hierarchical relationships between data.

• Common tree operations include traversal (inorder, preorder, postorder), insertion, deletion, and searching.

• Examples of tree-related coding challenges on NeetCode include implementing a binary search tree, finding the lowest common ancestor of two no...read more

Trees in leetcode are a common topic for coding interviews, involving various tree traversal and manipulation techniques.

• Understand different tree traversal methods like inorder, preorder, and postorder.

• Learn about common tree algorithms like finding the height, diameter, and lowest common ancestor.

• Practice solving tree-related problems on leetcode to improve your skills.

Processes are independent instances of a program, while threads are smaller units within a process sharing resources.

• Processes have their own memory space, while threads share the same memory space within a process.

• Processes are heavyweight, while threads are lightweight.

• Processes communicate with each other through inter-process communication mechanisms, while threads can communicate directly.

• Example: A web browser running multiple tabs is a process, and each tab running Jav...read more

Programming in C on linked list

• Understand the concept of linked list and its implementation in C

• Allocate memory dynamically using malloc()

• Use pointers to traverse and manipulate the linked list

• Handle edge cases such as empty list and deleting nodes

• Avoid memory leaks by freeing allocated memory

BGP (Border Gateway Protocol) is a routing protocol used to exchange routing information between autonomous systems on the internet.

• BGP is an exterior gateway protocol (EGP) that operates on TCP port 179.

• It is used to establish and maintain routing information among routers in different autonomous systems (ASes).

• BGP uses a path-vector algorithm to determine the best path for routing traffic.

• It supports both IPv4 and IPv6 networks.

• BGP allows routers to exchange information abo...read more

Merge sort implemented in a linked list

• Divide the linked list into two halves using slow and fast pointers

• Recursively sort each half

• Merge the sorted halves back together

Finding patterns in a stream of numbers involves analyzing the sequence for recurring trends or relationships.

• Look for repeating sequences or intervals in the numbers.

• Check for arithmetic progressions or geometric progressions.

• Consider using algorithms like sliding window or dynamic programming for efficient pattern detection.

Polymorphism is the ability of an object to take on many forms.

• Polymorphism allows objects of different classes to be treated as if they are of the same class.

• It is achieved through method overriding and method overloading.

• Example: A parent class Animal can have child classes like Dog, Cat, and Bird. All these child classes can have their own implementation of the method 'makeSound', but they can be treated as Animals.

• Polymorphism helps in achieving code reusability and flexi...read more

Data type is a classification of data based on the type of value it holds.

• Data type determines the type of operations that can be performed on the data.

• Examples of data types include integer, float, boolean, and string.

• Data types can be primitive or non-primitive.

• Primitive data types are predefined by the language and non-primitive data types are created by the programmer.

Next level account concepts involve advanced financial analysis, forecasting, budgeting, and strategic planning.

• Advanced financial analysis includes ratio analysis, trend analysis, and variance analysis.

• Forecasting involves predicting future financial performance based on historical data and market trends.

• Budgeting requires creating detailed financial plans for revenue and expenses.

• Strategic planning involves aligning financial goals with overall business objectives.

• Examples:...read more

Finding an equilibrium point in an array

• An equilibrium point is a position in an array where the sum of elements on the left is equal to the sum of elements on the right

• Iterate through the array and calculate the sum of elements on the left and right of each position

• If the sums are equal, return the position as the equilibrium point

• If no equilibrium point is found, return -1

Check if a binary tree is a Binary Search Tree (BST) by validating the inorder traversal.

• Perform an inorder traversal of the binary tree and store the elements in a list.

• Check if the list is sorted in ascending order. If yes, then the binary tree is a BST.

• Ensure that there are no duplicate elements in the binary tree.

DNS protocol is used to translate domain names to IP addresses on the internet.

• DNS stands for Domain Name System

• It translates human-readable domain names (like www.google.com) to IP addresses (like 172.217.3.206)

• DNS operates on a client-server model, with DNS servers hosting DNS records for different domains

• DNS queries are sent by clients to DNS servers to resolve domain names to IP addresses

TCP is a reliable, connection-oriented protocol while UDP is a faster, unreliable, connectionless protocol.

• TCP ensures data delivery and error checking while UDP does not.

• TCP establishes a connection before data transfer while UDP does not.

• TCP is used for applications that require reliable data transfer like email, file transfer, etc. while UDP is used for applications that require speed like online gaming, video streaming, etc.

Memory layout in C refers to how variables are stored in memory.

• Variables are allocated memory based on their data type

• Memory is divided into stack and heap

• Pointers store memory addresses

• Structs store data in contiguous memory locations

Reverse a string without using a loop.

• Use the built-in string manipulation functions in your programming language.

• Convert the string to an array of characters, reverse the array, and then convert it back to a string.

• Use recursion to reverse the string by swapping the first and last characters.

EVPN VXLAN topology explanation

• EVPN (Ethernet VPN) is a technology used to extend Layer 2 connectivity across a Layer 3 network

• VXLAN (Virtual Extensible LAN) is a tunneling protocol used to overlay virtualized Layer 2 networks over Layer 3 networks

• EVPN VXLAN topology combines the benefits of both technologies to provide scalable and flexible network virtualization

• It allows for efficient communication between virtual machines across different physical hosts or data centers

Scalable system design involves creating a system that can handle increased load and growth over time.

• Use microservices architecture to break down the system into smaller, independent services

• Implement load balancing to distribute traffic evenly across servers

• Utilize caching mechanisms to reduce the load on the database

• Design for horizontal scalability by adding more servers to handle increased load

• Consider using cloud services for scalability and flexibility

Reverse a linked list by changing the direction of pointers

• Start with three pointers: current, previous, and next

• Iterate through the linked list, updating pointers accordingly

• Set the next pointer of the current node to the previous node