40+ Diebold Nixdorf Interview Questions and Answers

Polymorphism is the ability of an object to take on many forms. Constructors and destructors are special methods in classes.

• Polymorphism allows objects to be treated as instances of their own class or as instances of their parent class.

• Constructors are used to initialize objects when they are created. Destructors are used to clean up after an object when it is destroyed.

• Classes are templates for creating objects. They define the properties and methods that an object will have...read more

Experienced change manager with knowledge of change management process, KPIs, PIR, CAB calls, and handling failed changes and difficult customers.

• Change management process involves planning, implementing, and monitoring changes to ensure successful outcomes

• KPIs associated with change management include reduction in downtime, increased efficiency, and improved customer satisfaction

• Experience with PIR (Post Implementation Review) and CAB (Change Advisory Board) calls to evaluat...read more

Mergesort is a divide-and-conquer algorithm that sorts an array by dividing it into two halves, sorting each half, and merging them.

• Divide the array into two halves

• Sort each half recursively

• Merge the two sorted halves

• Repeat until the entire array is sorted

• Example: ['apple', 'banana', 'cherry', 'date'] -> ['apple', 'banana', 'cherry', 'date'] -> ['apple', 'banana'], ['cherry', 'date'] -> ['apple'], ['banana'], ['cherry'], ['date'] -> ['apple', 'banana'], ['cherry', 'date'] -> ...read more

Sort an array of strings using a tree

• Create a binary search tree from the array

• Traverse the tree in-order and store the values in a new array

• Return the sorted array

Data can be passed in Angular from component to component using input properties, output properties, services, and state management libraries like NgRx.

• Use @Input decorator to pass data from parent to child component

• Use @Output decorator to emit events from child to parent component

• Use services to share data between components

• Use state management libraries like NgRx for complex data sharing scenarios

Check if a string is palindrome or not

• Reverse the string and compare with original

• Compare characters from start and end of string

• Ignore spaces and punctuation marks while comparing

Remove duplicates in linked lists

• Traverse the linked list and keep track of visited nodes using a hash table

• If a node is already visited, remove it from the linked list

• Time complexity: O(n), Space complexity: O(n)

I am comfortable with arrays, linked lists, stacks, queues, trees, and graphs.

• I have experience implementing algorithms using arrays, linked lists, stacks, queues, trees, and graphs.

• I am familiar with the time and space complexities of these data structures.

• I have used arrays for storing and accessing data in a linear fashion.

• I have used linked lists for dynamic memory allocation and efficient insertion and deletion operations.

• I have used stacks and queues for implementing al...read more

I am comfortable with multiple platforms including UNIX.

• I have experience working with UNIX-based systems such as Linux and macOS.

• I am also comfortable with Windows and have worked extensively with it.

• I am proficient in using command-line interfaces and have experience with scripting languages such as Bash and Python.

• I am adaptable and can quickly learn new platforms and technologies as needed.

The configuration will work by setting up the device according to the specified parameters.

• Configure the device settings based on the requirements

• Ensure compatibility between the configuration and the device

• Test the configuration to verify functionality

Stack and queue are data structures used to store and retrieve data in a specific order.

• Stack is a Last-In-First-Out (LIFO) data structure where the last element added is the first one to be removed. Example: undo/redo functionality in a text editor.

• Queue is a First-In-First-Out (FIFO) data structure where the first element added is the first one to be removed. Example: printing jobs in a printer queue.

• I have used stack and queue in various programming projects, such as imple...read more

GATE is not my preferred choice as I am more interested in software development than research.

• I am more interested in practical application of software development than theoretical research

• I believe my skills and interests align better with software engineering roles

• I have researched and found that software engineering roles do not require a GATE qualification

I would rate myself as proficient in both C and Java.

• I have extensive experience in both languages, having worked on multiple projects using them.

• I am comfortable with the syntax and can write efficient and optimized code.

• I am familiar with the standard libraries and can use them effectively.

• I am always learning and improving my skills in both languages.

• For example, in C, I have worked on projects involving embedded systems and low-level programming, while in Java, I have dev...read more

Encryption methods include symmetric key, asymmetric key, hashing, and quantum encryption.

• Symmetric key encryption uses the same key for both encryption and decryption.

• Asymmetric key encryption uses a public key for encryption and a private key for decryption.

• Hashing converts data into a fixed-length string of characters.

• Quantum encryption uses the principles of quantum mechanics to encrypt data.

• Examples of encryption algorithms include AES, RSA, SHA-256, and QKD.

Computer hardware peripherals work by connecting to the computer and providing additional functionality.

• Peripherals connect to the computer through various ports such as USB, HDMI, or VGA.

• They are powered by the computer or an external power source.

• Examples of peripherals include printers, scanners, keyboards, mice, and monitors.

• Each peripheral has its own driver software that allows it to communicate with the computer.

• Peripherals can be added or removed from the computer wit...read more

Reverse words in a string

• Split the string into an array of words

• Reverse the array

• Join the array into a string

Encapsulation is the process of hiding implementation details and exposing only the necessary information to the user.

• Encapsulation is achieved through access modifiers like public, private, and protected.

• It helps in achieving data abstraction and information hiding.

• Encapsulation provides better control over the data and prevents unauthorized access.

• Example: A class with private variables and public methods to access those variables.

• Encapsulation is one of the four fundamenta...read more

Single core processors have one processing unit while multi core processors have multiple processing units.

• Single core processors can only handle one task at a time while multi core processors can handle multiple tasks simultaneously.

• Multi core processors are generally faster and more efficient than single core processors.

• Single core processors are becoming less common as technology advances and multi core processors become more affordable.

• Examples of single core processors i...read more

Multithreading allows for concurrent execution of multiple threads within a single process, improving performance and responsiveness.

• Multithreading can improve performance by allowing multiple tasks to be executed simultaneously

• Applications include GUI programming, web servers, and scientific simulations

• Threads share memory and resources within a process, while processes have their own memory and resources

• Thread communication and synchronization can be challenging and require...read more

Windows 7 is a newer version of Windows than XP, with improved features and security.

• Windows 7 has a more user-friendly interface

• Windows 7 has better security features, such as BitLocker encryption

• Windows 7 supports newer hardware and software

• Windows 7 has improved performance compared to XP

• Windows 7 has a built-in virtual assistant, Cortana, which XP does not have

LAN stands for Local Area Network, WAN stands for Wide Area Network. Connections refer to the way devices communicate with each other.

• LAN is a network that connects devices in a limited area, like a home or office.

• WAN is a network that connects devices over a larger geographical area, like different cities or countries.

• Connections can be wired or wireless, using technologies like Ethernet or Wi-Fi.

• Devices in a network can include computers, printers, routers, and servers.

Reverse a given string

• Create an empty string

• Iterate through the original string in reverse order

• Append each character to the empty string

• Return the reversed string

Troubleshooting network issues involves identifying the switch causing the problem and using various techniques to resolve it.

• Identify the switch experiencing the issue by checking network logs or using network monitoring tools.

• Verify physical connections and configurations on the switch to ensure they are correct.

• Use command line tools like ping, traceroute, and netstat to diagnose network connectivity problems.

• Check for any network congestion or bandwidth issues that may be...read more

I code for at least 6 hours daily.

• I spend most of my workday coding.

• I also code for personal projects outside of work.

• I take breaks to avoid burnout and maintain productivity.

ATM machines have a standard structure with a few variations depending on the manufacturer.

• ATM machines typically have a screen for displaying information and a keypad for entering data

• They also have a card reader for reading bank cards and a dispenser for cash

• Some ATMs may also have additional features such as a printer for receipts or a deposit slot for checks

• The structure may vary slightly depending on the manufacturer or location, but the basic components remain the same

Computer peripherals are devices that connect to a computer to enhance its functionality.

• Peripherals include input devices like keyboards and mice, output devices like monitors and printers, and storage devices like external hard drives.

• They connect to the computer through ports like USB, HDMI, and VGA.

• Peripherals require drivers to communicate with the computer's operating system.

• Examples of peripherals include webcams, scanners, and speakers.

I rate myself 8/10 in C and 9/10 in Java.

• Strong understanding of data structures and algorithms

• Experience in developing applications using both languages

• Familiarity with debugging and troubleshooting

• Regularly update my knowledge through online resources and courses

MAC address is a unique identifier assigned to network interfaces for communications at the data link layer, while IP address is a unique identifier assigned to devices for communications at the network layer.

• MAC address is a hardware address that uniquely identifies a device on a network.

• IP address is a logical address that identifies a device on a network.

• MAC address is assigned by the manufacturer and usually does not change.

• IP address is assigned by the network administra...read more

Code to check if a given string is a palindrome or not.

• Create a function that takes a string as input

• Remove all non-alphanumeric characters and convert to lowercase

• Compare the original string with its reverse to check for palindrome

OOPs concepts are fundamental principles of object-oriented programming, including inheritance, encapsulation, polymorphism, and abstraction.

• Inheritance: Allows a class to inherit properties and behavior from another class. Example: Animal class can inherit from Mammal class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit. Example: Using private variables and public methods in a class.

• Polymorphism: Ability of a function to behave different...read more

Encryption is the process of converting plain text into a coded message, while decryption is the reverse process.

• Encryption uses an algorithm to scramble the original message into an unreadable format

• Decryption uses a key to convert the encrypted message back into its original form

• Encryption is used to protect sensitive information from unauthorized access

• Examples of encryption include SSL, AES, and RSA

VPN stands for Virtual Private Network, a secure connection that allows users to access the internet privately and securely.

• VPN encrypts data to ensure privacy and security

• It masks the user's IP address to protect their identity

• Commonly used for remote work, accessing geo-blocked content, and enhancing online security

• Examples include NordVPN, ExpressVPN, and CyberGhost

To configure IP in Outlook, go to Account Settings and update the server settings with the correct IP address.

• Open Outlook and go to File > Account Settings.

• Select the email account you want to configure and click on Change.

• In the Server Settings section, update the incoming and outgoing mail server with the IP address.

• Save the changes and test the connection by sending a test email.

Switch forwards data to specific devices based on MAC addresses, while hub broadcasts data to all connected devices.

• Switch operates at the data link layer (Layer 2) of the OSI model, while hub operates at the physical layer (Layer 1).

• Switch is more efficient as it reduces network congestion by only sending data to the intended recipient, while hub causes more collisions and traffic.

• Examples: Cisco Catalyst Switch, Netgear Ethernet Hub.

Kubernetes is an open-source container orchestration platform for automating deployment, scaling, and managing containerized applications.

• Automates deployment, scaling, and management of containerized applications

• Provides self-healing capabilities for applications

• Supports horizontal scaling for better resource utilization

• Offers declarative configuration for easy management

• Allows for rolling updates and rollbacks of applications

RAM in a PC stands for Random Access Memory, which is a type of computer memory that can be accessed randomly.

• RAM is a type of volatile memory that stores data and machine code currently being used by the CPU.

• It allows for quick read and write access to data, which helps improve the overall performance of a computer.

• Examples of RAM include DDR4, DDR3, and LPDDR4.

Components of a motherboard include CPU, RAM, GPU, BIOS, SATA ports, USB ports, and expansion slots.

• CPU (Central Processing Unit)

• RAM (Random Access Memory)

• GPU (Graphics Processing Unit)

• BIOS (Basic Input/Output System)

• SATA ports

• USB ports

• Expansion slots

SAO is a monolithic architecture while Microservices is a distributed architecture.

• SAO is a single large application with all components tightly coupled, while Microservices is a collection of small, independent services.

• SAO is harder to scale and maintain, while Microservices allows for easier scalability and maintenance.

• SAO can lead to longer development cycles and slower deployment, while Microservices enables faster development and deployment cycles.

• SAO may have a single ...read more

RAM stands for Random Access Memory, used for temporary storage of data that can be accessed quickly. ROM stands for Read-Only Memory, used for permanent storage of data that cannot be easily modified.

• RAM is volatile memory that stores data temporarily while the computer is on

• ROM is non-volatile memory that stores data permanently and cannot be easily modified

• RAM is faster but loses data when power is turned off

• Examples of RAM include DDR4, DDR3, etc.

• Examples of ROM include B...read more