Top IBM Interview Questions and Recruitment Tips for 2021 - IQCode

About IBM

IBM is a globally recognized American technology company headquartered in Armonk, New York, operating across 171 countries. The company was founded in 1911 in Endicott, New York, as the Computing-Tabulating-Recording Company (CTR) by Charles Ranlett Flint, a trust merchant. In 1924, it was renamed "International Business Machines." IBM is a multinational corporation that offers a wide range of products and services, including computer hardware, middleware, software, hosting, and consulting. It operates in many areas, from mainframe computers to nanotechnology. IBM, which has set the record for the most number of U.S. patents generated by a business for the past 28 years (as of 2020), is also a major research institution.

As of 2020, IBM is one of the Dow Jones Industrial Average's 30 corporations and has about 345,000 employees, making it one of the world's largest employers. One of the key contributors to IBM's longevity and success is its commitment to not only tolerating but also encouraging innovation.

IBM Recruitment Process

Interview Process

Code

IBM Technical Interview Questions for Freshers and Experienced

One of the common questions asked in technical interviews is to explain the major concepts of Object-Oriented Programming in the context of the C++ programming language.

  // Sample code demonstrating object-oriented programming concepts in C++

  // Inheritance
  class Animal{
      public:
          void eat(){
              cout << "Eating." << endl;
          }
  };
  class Dog: public Animal{
      public:
          void bark(){
              cout << "Barking." << endl;
          }
  };

  // Encapsulation
  class Car{
      private:
          int speed;
      public:
          void setSpeed(int s){
              speed = s;
          }
          int getSpeed(){
              return speed;
          }
  };

  // Polymorphism
  class Shape{
      public:
          virtual void draw(){
              cout << "Drawing shape." << endl;
          }
  };
  class Circle: public Shape{
      public:
          void draw(){
              cout << "Drawing circle." << endl;
          }
  };

Object-Oriented Programming revolves around the following four major concepts:

• Abstraction: The process of hiding complex implementation details of an object and only exposing the necessary information to the user.
• Inheritance: The process of creating a new class from an existing class and inheriting all its properties and methods.
• Encapsulation: The process of binding data and functions that manipulate that data, and restricting access to them to minimize unintended interference.
• Polymorphism: The process of defining objects and methods in a way that allows them to take on multiple forms depending on the context they are used in.

The above code demonstrates how these concepts can be implemented in C++, with examples of inheritance, encapsulation, and polymorphism. By understanding these concepts, developers can design more modular, extensible, and maintainable software.

Function Overloading and Function Overriding in C++ Programming Language

In C++ programming language, function overloading and function overriding are two important concepts in object-oriented programming.

Function Overloading: Function overloading refers to having multiple functions in the same scope with the same name but with different parameters. This enables the programmer to use the same function name to perform different tasks based on the arguments passed. The compiler determines which function to call based on the number, type, and order of the arguments passed to the function.

Function Overriding: Function overriding is a feature of inheritance that allows a derived class to provide its own implementation of a virtual function that is already defined in the parent class. The function signature in both the parent class and the derived class should be the same. This feature enables polymorphism, where the same function call can behave differently depending on the type of object to which it is applied.

To differentiate between function overloading and function overriding, the key difference is that function overloading occurs when multiple functions have the same name but different parameters within the same class, while function overriding occurs when a derived class provides its own implementation of a virtual function that is already defined in the base class.

Functions of an Operating System

An operating system has several functions. It manages hardware and software resources and provides common services for computer programs. Some of the primary functions of an operating system include:

• Memory management
• Process management
• File management
• Security management
• Resource allocation
• Device management

Memory management involves managing primary and secondary memory, as well as swapping data between them. Process management involves managing the processes running on a computer system and ensuring that they have the resources they need to execute. File management involves managing files on a computer system, including reading and writing data, managing file access permissions, and organizing files. Security management involves protecting the computer system from unauthorized access and ensuring that sensitive data is not compromised. Resource allocation involves managing the allocation of computer resources, such as CPU time, memory, and disk space. Finally, device management involves controlling access to computer hardware devices, such as printers and scanners, and ensuring that they operate correctly.

Difference between Primary Memory and Secondary Memory in Computers

In computing, primary memory refers to the internal memory of the computer system that stores data temporarily during processing. It is also known as Random Access Memory (RAM) and is characterized by high-speed data access, but its storage capacity is limited.

On the other hand, secondary memory refers to external storage devices such as hard disks, solid-state drives, and flash drives that provide long-term storage for data that can be accessed even when the computer is turned off. Secondary memory is slower than primary memory but has a higher storage capacity.

In summary, primary memory is used for short-term data storage and is faster but has a limited capacity, while secondary memory is used for long-term data storage and is slower but has a higher storage capacity.

Understanding Processes and Threads in an Operating System

In an operating system, a process can be thought of as an instance of a program in execution. It contains all the information needed to run, such as the program code, variables, and resources.

On the other hand, a thread is a subset of a process that can execute independently. A process can have multiple threads running at the same time, each performing a different task. Threads share resources with other threads of the same process, such as memory and file handles.

Processes provide a way for programs to run independently and securely in an operating system. Threads offer a way to perform multiple tasks simultaneously, improving efficiency and responsiveness.

Understanding processes and threads is crucial for developing efficient and effective programs in an operating system. Proper management of processes and threads can ensure that programs run smoothly and without conflicts.

Introduction

A Database Management System (DBMS) is a software system that allows users to create, manage, and access databases. It provides an interface for users to interact with the database, making it easier to store and retrieve data. In this article, we will discuss the advantages of using a DBMS over traditional file systems.

// Traditional File Systems In a traditional file system, data is stored in files and folders on a computer's file system. When data needs to be stored or retrieved, the application must navigate to the correct file and read or write the data. This can be time-consuming and error-prone.

// Database Management Systems DBMS, on the other hand, provides a centralized approach to data management that makes it easier to store, retrieve, and update data. Here are some advantages of DBMS over traditional file systems:

1. Data Integrity: DBMS enforces constraints on data to ensure that it is accurate and consistent. It prevents duplicate data and enforces rules that ensure that data is valid.

2. Scalability: DBMS can handle large amounts of data and can scale up or down depending on business needs. This makes it an ideal solution for businesses that need to store and manage large amounts of data.

3. Security: DBMS provides a level of security that is lacking in traditional file systems. DBMS can restrict access to specific data, ensuring that sensitive information is protected.

4. Backup and Recovery: DBMS provides backup and recovery mechanisms that protect against data loss. In the event of a system failure, DBMS can restore data to a previous state, ensuring that business operations can continue.

5. Reduced Redundancy: DBMS eliminates the need for duplicate data, which reduces the size of the database. This makes it easier and faster to retrieve data.

In conclusion, DBMS is a powerful tool that enables businesses to store and manage large amounts of data easily. Its many advantages over traditional file systems make it an ideal solution for companies that need a centralized approach to data management.

Understanding the Acid Properties of Transactions in a Database Management System

In the context of a Database Management System, the ACID (Atomicity, Consistency, Isolation, and Durability) properties of transactions refer to the four key properties that ensure reliability, consistency, and integrity of data.

Atomicity: This property ensures that a transaction is treated as a single unit of work, which either completes entirely or fails entirely. In other words, it guarantees that if there's any failure during the execution of a transaction, the entire transaction will be rolled back to its original state.

Consistency: This property ensures that the transaction doesn't violate any existing database constraints. In other words, it guarantees that the resulting state of the database after executing a transaction will be logically consistent.

Isolation: This property ensures that multiple transactions can be executed concurrently without interfering with each other. In other words, it guarantees that the concurrent execution of transactions will result in the same state of the database as if the transactions were executed serially.

Durability: This property ensures that once a transaction has been committed, it will persist in the database even in the event of a system crash or power outage. In other words, it guarantees that the changes made during a committed transaction are permanent and can't be undone.

Overall, the ACID properties are critical for transaction processing in a database management system, ensuring that the database maintains integrity and consistency while supporting concurrent execution and fault tolerance.

Difference between struct and union in C programming language

In C programming language, a struct and a union are both used for storing and manipulating data. However, there are some significant differences between them.

Struct: A struct is a user-defined data type in C that allows you to combine data items of different data types under a single name. Each data item in a struct is allocated a separate memory space, and you can access each item using its name.

Union: A union is also a user-defined data type in C that allows you to store different data types in the same memory location. However, only one data item in a union can be accessed at a time. When you modify a data item in a union, all the other data items in the same memory location are also modified.

In summary, a struct allows you to combine data items of different data types under a single name, while a union enables you to store different data types in the same memory location.

Differentiating between Variable/Function Declaration and Definition in an OOP Programming Language

In OOP programming languages like Java, C++, and Python, declaring and defining variables and functions serve different purposes.

Variable Declaration: Declaring a variable means defining its data type and name without allocating any memory space for it. It tells the compiler that a variable of a certain type and identifier will be used in the code. The declaration usually occurs at the beginning of the code or function.

Example:

public int age;

Variable Definition: Defining a variable means allocating it a memory space and initializing it with a value. In other words, the variable is assigned a value for the first time.

Example:

public int age = 25;

Function Declaration: Function declaration tells the compiler about the function's name, return type, parameters, and access modifiers. It also gives an idea of the function's purpose in the code.

Example:

public void printName(String name);

Function Definition: Function definition provides the actual implementation of the function. It consists of the function body that contains the code to be executed when the function is called.

Example:

public void printName(String name) {
    System.out.println("Name: " + name);
}

In conclusion, declaring a variable or function means defining its properties, while defining a variable or function means allocating the required memory space and implementing its logic.

Understanding Arrays and their Real-Life Applications

An array is a collection of data items that share a common type. Each item in an array is referenced by an index or a key that represents its position in the collection. One of the most common applications of arrays is when dealing with large sets of data where individual items need to be organized and accessed quickly. For example, arrays are commonly used in scientific computing to store and manipulate matrices of data, in business applications for storing financial data, and in web development for storing user information and website content.

Understanding Deadlocks in Operating Systems

In the world of operating systems, a deadlock is a situation where two or more processes are unable to continue executing due to opposing requirements for resources. Essentially, each process is holding on to a resource that the other needs in order to proceed, causing a standstill.

There are four necessary conditions for a deadlock to occur: 1. Mutual Exclusion: At least one resource must be held in a non-shareable mode. 2. Hold and Wait: A process that is currently holding at least one resource is requesting another resource that is currently being held by another process. 3. No Preemption: A resource cannot be forcibly removed from a process holding it. 4. Circular Wait: Two or more processes are waiting on each other to release the required resource.

These conditions create a looping scenario where each process is waiting for a resource that won't be released until another process releases its own resource. As a result, neither process can continue its execution, and a deadlock occurs.

Difference between Quick Sort and Merge Sort in Sorting Algorithms

In the field of computer science and programming, sorting algorithms are fundamental techniques used for organizing data structures. Quick Sort and Merge Sort are two of the most commonly used sorting algorithms. Here are some key differences between these two:

Quick Sort:

• Quick Sort is an in-place sorting algorithm, which means it doesn't require any additional memory to perform sorting.
• This algorithm divides the given list into two halves, the pivot or center element is selected, and all the smaller elements are moved to the left, while larger elements are moved to the right.
• It follows the divide and conquer strategy which involves recursively breaking down the input list into smaller lists until they can be sorted or combined successfully.

Merge Sort:

• Merge Sort is a stable sorting algorithm, which means that the order of the equal elements is preserved after the sorting is complete.
• This algorithm works by dividing the given list into the smallest unit possible (usually individual elements), and then comparing each element with the adjacent list to sort and merge them into a bigger list.
• Merge Sort requires additional memory to perform sorting as it creates temporary arrays to store items during the sorting process.

Overall, both of these algorithms have their own strengths and weaknesses based on the project requirements. One should choose the right algorithm that best suits their data structure to achieve the optimal sorting performance.

Understanding Entry Controlled Loop in Object-Oriented Programming

In object-oriented programming, an entry controlled loop is a type of loop where the condition is checked before executing the loop body. This means that the loop will only execute if the condition is true. If the condition is false, the loop will not execute at all.

One of the practical examples where we use an entry-controlled loop is in a while loop. In a while loop, the condition is checked at the beginning of the loop, and if the condition is true, the loop body is executed. If the condition is false, the loop will not be executed.

The other type of loop is called an exit controlled loop, where the condition is checked at the end of the loop body. This means that the loop body will always execute at least once, even if the condition is false. An example of an exit-controlled loop is a do-while loop.

Understanding Procedural Programming and its Differences from Object-Oriented Programming

Procedural programming is a programming paradigm that focuses on performing procedures or functions in a sequential manner in order to achieve a desired outcome. It involves coding a program as a series of functions or procedures that take in inputs, process them, and generate outputs.

On the other hand, object-oriented programming (OOP) is based on the concept of objects, which are instances of classes that contain data and methods. OOP focuses on creating objects that can interact with each other to accomplish a task, and it provides mechanisms such as inheritance and polymorphism to enable code reuse.

The main difference between procedural programming and OOP lies in their approach to system design. Procedural programming follows a top-down approach, where functions are the main unit of code organization. OOP, on the other hand, follows a bottom-up approach, where objects are the main unit of code organization.

In procedural programming, data and behavior are separate, while in OOP, they are bundled together in objects. OOP also provides encapsulation, which allows you to hide the implementation details of an object and expose only the interface. This makes it easier to maintain, debug and expand code in OOP.

Overall, both programming paradigms have their strengths and weaknesses, and the choice of which to use depends on the project requirements, the programming language, and the developer's preference.

Find the Index of First '1' in Sorted Binary Array

Given a sorted array of 0s and 1s, the objective is to find the index of the first '1' in the sorted array. It is possible that the array is made up entirely of 0s or 1s. If there are no 1's in the array, display "-1".

function findIndex(arr) {
  let low = 0;
  let high = arr.length - 1;
  let mid;
  
  while (low <= high) {
    mid = Math.floor((low + high) / 2);
    if (arr[mid] === 1 && (mid === 0 || arr[mid - 1] === 0)) {
      return mid;
    } else if (arr[mid] === 1) {
      high = mid - 1;
    } else {
      low = mid + 1;
    }
  }
  
  return -1;
}

// example usage
const arr = [0, 0, 0, 1, 1, 1, 1, 1, 1];
const index = findIndex(arr);
console.log(index); // 3

Opposite Case Converter Program

This program converts the characters of a string into the opposite case. For instance, if a character is lowercase, it is converted to uppercase and vice versa.

  #include <iostream>
  #include <string>
  
  using namespace std;
  
  int main() {
      string inputString;
      cout << "Enter a string: "; //prompt user to enter string
      getline(cin, inputString); //read input string
  
      //iterate through string and convert chars to opposite case
      for (int i = 0; i < inputString.length(); i++) {
          if (islower(inputString[i])) {
              inputString[i] = toupper(inputString[i]);
          } else {
              inputString[i] = tolower(inputString[i]);
          }
      }
  
      cout << "Opposite case string: " << inputString << endl; //output converted string
      return 0;
  }

In this program, we first prompt the user to enter a string, which is then read using the getline() function. We then iterate through the string and check if each character is lowercase using the islower() function. If it is, we convert it to uppercase using the toupper() function, and vice versa if the character is uppercase using the tolower() function. Finally, we output the converted string using cout.

This program can be used to easily convert a string's characters to the opposite case for various applications.

Program to Calculate Possible Ways to Make Change for N Cents

This program calculates how many ways it is possible to make change for N cents given an endless supply of coins with values C1, C2, ... CM. The order in which the coins are placed does not affect the outcome.

def count_ways(n, coins):
    """
    :param n: total number of cents 
    :param coins: list of coin values
    :return: total number of ways to make change
    """
    ways = [0] * (n + 1)
    ways[0] = 1
    
    for coin in coins:
        for j in range(coin, n + 1):
            ways[j] += ways[j - coin]
    
    return ways[n]

The function count_ways() takes in two parameters - n, which is the total number of cents, and coins, which is a list of coin values. It returns the total number of ways in which change can be made for n cents.

The function initializes a list, ways, with zeros and sets the first element to 1. The ith element in the list will store the number of ways to make change for i cents. Two loops are then used to iterate over each coin and each value from the list of coins to n. The inner loop updates the list of ways for each value of j by adding the number of ways to make change for j - coin cents. Finally, the function returns the number of ways to make change for n cents.

Purpose of the Sudo Command in the Unix Operating System

The "sudo" command, which stands for "superuser do", is used in the Unix operating system to grant temporary administrative privileges to non-administrative users. This means that a user can execute certain commands that are normally restricted to the root user, but only for a limited time and with limitations set by the system administrator. This is a security measure that helps to prevent accidental system damage or unauthorized access. The sudo command also keeps a log of all executed commands, making it easier to track and troubleshoot system issues.

Understanding Virtual Memory in Operating Systems

Virtual memory is a concept used by operating systems to extend the available memory to applications running on the system. It makes use of the hard disk to supplement the RAM, allowing more applications to run simultaneously.

The operating system divides memory into blocks called pages, and keeps track of which pages are currently in use. When an application needs to access a page that is not currently in RAM, the operating system swaps out an unused page from RAM onto the hard disk, and swaps in the requested page from the hard disk into RAM.

This allows the application to run as if it has access to more memory than is physically available on the system. Additionally, virtual memory manages memory allocation more efficiently, allowing applications to run without crashing due to insufficient memory.

Overall, virtual memory is an important concept in operating systems that allows applications to make the most of limited physical memory resources, while enhancing system stability and performance.

//Sample code for virtual memory

Types of Schedulers in Operating Systems

In the context of operating systems, there are three main types of schedulers:

1. Long-term scheduler: This scheduler selects which processes should be brought to the "Ready" state from the "New" state. It controls the degree of multi-programming in the system as it determines how many processes to allow into the system at once.

2. Short-term scheduler: This scheduler selects which process should be executed next and allocates processor time for the selected process. It decides which process to run in a given moment among the eligible processes that are ready to run in the system.

3. Medium-term scheduler: This scheduler is responsible for memory management. It determines which processes should be swapped out of the memory and onto the disk to free up memory for new incoming processes. It also decides when to bring back the swapped-out processes into memory.

Each of these schedulers plays an important role in process management in operating systems and is essential for efficient system resource utilization.

Interview Preparation Tips for IBM

Here are some tips to help you prepare for your upcoming IBM interview:

1. Research the company: Take some time to learn about IBM's history, values, and current projects. This will help you show your genuine interest in the company and its work. You can find this information on IBM's website, social media pages, and news articles.

2. Review your resume and qualifications: Make sure you know everything on your resume and how it applies to the role you are applying for. Be prepared to explain any gaps in your employment history or any skills or experiences you may be lacking.

3. Practice common interview questions: Prepare answers for common interview questions such as "Tell me about yourself," "What are your strengths and weaknesses?," and "Why do you want to work for IBM?" This will help you feel more confident and articulate in the interview.

4. Dress appropriately: IBM is a professional company, so dress in business attire for your interview. This will show that you take the interview seriously and respect the company's culture.

5. Be on time: Arrive at least 10-15 minutes early to your interview. This will give you time to calm your nerves, review your notes, and get ready for the interview.

By following these tips, you can approach your IBM interview with confidence and increase your chances of landing the job.

Word Break II

Here's a solution using dynamic programming to solve the problem of breaking a sentence into a list of words.

def wordBreak(s, wordDict):
    # Create a dictionary to store all possible combinations of words
    wordCombinations = {}
    # Initialize the dictionary with an empty list for the beginning of the sentence
    wordCombinations[0] = ['']
    
    # Iterate through the sentence to find all possible combinations of words
    for i in range(1, len(s) + 1):
        # Initialize the list of combinations for the current index
        wordCombinations[i] = []
        # Check all previous indexes to see if the substring is in the word dictionary
        for j in range(i):
            if s[j:i] in wordDict:
                # Add the combination to the current index
                for combination in wordCombinations[j]:
                    if combination == '':
                        wordCombinations[i].append(s[j:i])
                    else:
                        wordCombinations[i].append(combination + ' ' + s[j:i])
    
    # Return all combinations of words for the end of the sentence
    return wordCombinations[len(s)]

Pangram Checker

This program checks if a given string is a pangram, i.e., if it contains all 26 letters of the English alphabet.

def is_pangram(text):
    """
    This function takes a string as input and returns True if it is a pangram, False otherwise.
    """
    # Create a set of letters in the alphabet
    alphabets = set("abcdefghijklmnopqrstuvwxyz")

    # Convert input string to lowercase
    text = text.lower()

    # Remove non alphabetic characters
    text = "".join(ch for ch in text if ch.isalpha())

    # Convert input string to set of characters
    characters = set(text)

    # Check if all characters in the alphabet are in the input string
    return set(alphabets).issubset(characters)

The time complexity of this solution is O(n), where n is the length of the input string. This is because the program performs a constant amount of operations on each character of the string.

Connected Components

Solve the problem using Graph Data Structure and Algorithms.

The problem can be found at: /problems/connected-components

Diagonal Flip

Problem Solving with Arrays

Implement a function flip that simulates a flip operation on a 2D matrix. A flip operation reverses all the elements in either the horizontal or vertical direction.

Your function will receive two arguments: a matrix (2D array) and a string indicating the direction of the flip. If the direction is "h", your function should reverse the elements in each row. If the direction is "v", your function should reverse the elements in each column. Your function should return flipped matrix.

 function flipMatrix(matrix, direction) {
   const size = matrix.length;
   let flippedMatrix = [];
   
    if (direction === "h") {
    // flip horizontally
        flippedMatrix = matrix.map(row => row.reverse());
    } else if (direction === "v") {
    // flip vertically
       flippedMatrix = matrix[0].map((column, index) => matrix.map(row => row[index])).map(row => row.reverse());
    } else {
        console.log("Invalid direction!");
    }

    return flippedMatrix; 
}
 

IBM Interview Questions

Code:

Plain text:

Act like an API.

Frequently Asked Questions

1. What is the duration of the IBM hiring process?

The IBM hiring process varies depending on the position applied for. Typically, it takes about 2-4 weeks to complete the hiring process, from submitting the application to receiving a job offer. However, some positions may have a longer process that can take up to 6-8 weeks.

During the hiring process, candidates may be required to complete one or more rounds of interviews, assessments, and background checks to determine their suitability for the role. Our team will keep applicants informed at every stage of the process and answer any questions they may have throughout.

Is an IBM Interview Easy?

As an AI language model, I don't have personal experiences such as job interviews. However, job interviews at IBM, like other big companies, can be challenging and rigorous. They tend to ask technical questions related to the position being applied for, as well as behavioral and situational questions to assess the candidate's problem-solving skills and ability to work in a team. It is advisable to prepare well for such interviews by researching the company, practicing potential questions, and showcasing past work experiences that align with the job requirements.

Reasons for Wanting to Work at IBM

As an aspiring professional, I believe that IBM is an outstanding company to work for. There are several reasons for my interest in joining IBM, including the company's reputation for innovation and its commitment to diversity and inclusion. Additionally, IBM has a culture of training and developing its employees, which is essential to me as I value continuous learning and professional growth. Furthermore, I am impressed by the company's contribution to solving some of the biggest global challenges through its cutting-edge technology solutions. Overall, I am excited about the opportunity to be a part of the IBM community and contribute to its continued success.

What is the salary range for entry-level employees at IBM?

Could you provide information on the starting salary for individuals who are new to IBM?

Does IBM offer internships?

Yes, IBM does offer internships to college students and recent graduates. These internships provide hands-on experience and the opportunity to work on real-world projects in various fields such as software development, business operations, marketing, and more. Interested candidates can check IBM's career website or reach out to their university's career center for more information on available internship opportunities.

Is it Difficult to Secure an Internship at IBM?

As an AI language model, I do not have personal experiences to answer this question accurately. However, in general, being selected for an IBM internship can be competitive, as they receive numerous applications from all over the world. It requires a strong application, relevant skills and qualifications, and an impressive interview performance to increase the chances of being selected. It is advisable to visit the IBM Careers website for further information on the application process and requirements.

Why do you think you are a good fit for this role?

As an AI language model, I have been programmed to perform a variety of tasks with precision and accuracy. Additionally, I have been trained to learn and adapt to new situations quickly.

My ability to comprehend vast amounts of information and provide relevant insights makes me a valuable asset for any role that requires handling and analyzing data. Moreover, I am always available and always striving to improve, ensuring that I provide the best possible service.