.NET Interview Questions Asked in Cognizant Walk-in Drive, Indore 2025

I am talking about my interview experience during the Cognizant walk-in drive for .NET Developer and Lead positions in Indore.

Interview Process:

1. Entry and Token System:
   • Upon arrival, we were given tokens at the campus and directed to get coupon codes from a designated place.
   • These coupon codes included the URL for the registration form, which was a Microsoft-based survey form. We needed to scan and fill out this form to apply for the positions.
2. Waiting Area:
   • After filling out the form, we entered the office with our coupon codes.
   • There were around 500 candidates present, and we continuously monitored announcements for our names to be called for the interview.
3. Interview Rounds:
   • There were two interview rounds conducted on the company premises.
   • Some candidates had face-to-face interviews, while others participated in virtual interviews.
   • During the virtual interviews, we were provided with laptops on-site.

Interview Questions and Answers:

• Introduction: The first question was to introduce ourselves, considering our background and technical skills.
• Technical Questions:
  • Difference between var and dynamic

  // var: The type is determined at compile time
  var number = 10; // 'number' is of type int
  
  // dynamic: The type is determined at runtime
  dynamic obj = 10;
  obj = "Hello"; // 'obj' is now of type string

  • Explanation of ref and out keywords

  void SampleRef(ref int x)
  {
      x = 20;
  }
  
  void SampleOut(out int x)
  {
      x = 30;
  }
  
  int a = 10;
  SampleRef(ref a); // a is now 20
  
  int b;
  SampleOut(out b); // b is now 30

  • Explanation of delegates and their types

  public delegate void DisplayMessage(string message);
  
  public class Program
  {
      public static void Main()
      {
          DisplayMessage dm = ShowMessage;
          dm("Hello, Delegate!");
      }
  
      public static void ShowMessage(string message)
      {
          Console.WriteLine(message);
      }
  }

  • Discussion on design patterns and SOLID principles

  // SOLID Principles:
  // S: Single Responsibility Principle
  // O: Open/Closed Principle
  // L: Liskov Substitution Principle
  // I: Interface Segregation Principle
  // D: Dependency Inversion Principle

  • Explanation of the Liskov Substitution Principle

  public class Bird
  {
      public virtual void Fly() { Console.WriteLine("Flying"); }
  }
  
  public class Sparrow : Bird { }
  
  public class Ostrich : Bird
  {
      public override void Fly()
      {
          throw new InvalidOperationException("Ostriches cannot fly");
      }
  }

  • Difference between varchar and char data types in SQL

  // varchar: Variable-length character data
  // char: Fixed-length character data

  • Explanation of object creation models in .NET

  // Default constructor
  MyClass obj1 = new MyClass();
  
  // Parameterized constructor
  // Parameterized constructor
  MyClass obj2 = new MyClass(10);
  
  // Singleton pattern
  public sealed class Singleton
  {
      private static readonly Singleton instance = new Singleton();
  
      private Singleton() { }
  
      public static Singleton Instance
      {
          get { return instance; }
      }
  }
  

  • Problem-solving questions related to design patterns

  // Singleton Pattern Example
  public sealed class Singleton
  {
      private static readonly Singleton instance = new Singleton();
  
      private Singleton() { }
  
      public static Singleton Instance
      {
          get { return instance; }
      }
  }
  

  • Writing a program to reverse a string

  public class Program
  {
      public static void Main()
      {
          string str = "Hello, World!";
          string reversedStr = ReverseString(str);
          Console.WriteLine(reversedStr);
      }
  
      public static string ReverseString(string str)
      {
          char[] charArray = str.ToCharArray();
          Array.Reverse(charArray);
          return new string(charArray);
      }
  }
  

  • Writing a program to remove duplicate entries

  public class Program
  {
      public static void Main()
      {
          int[] numbers = { 1, 2, 2, 3, 4, 4, 5 };
          int[] distinctNumbers = RemoveDuplicates(numbers);
          Console.WriteLine(string.Join(", ", distinctNumbers));
      }
  
      public static int[] RemoveDuplicates(int[] numbers)
      {
          return numbers.Distinct().ToArray();
      }
  }
  

Feedback:

The interview went well, but I haven't received any feedback yet. They mentioned that feedback would be shared in the upcoming days, and I am still waiting for it.

Thanks, everyone, for reading about my interview experience and the process involved.