C#

1. What is the difference between value and reference types? Is it true that the value type is always stored in a stack?

2. What is the output for this block of code?

struct Num 
{ 
     public int i;
}
class MyProgram
{ 
     static void Main()
     {
          Num x = new Num(); 
          x.i = 10; 
          Update(x); 
          Console.Write(x.i);
     }
     static void Update(Num y)
     {
          y.i = 20; 
     } 
}

3. What is the difference between classes and structures? Is it possible to inherit from structure? In what cases it's better to use structures?

4. What is the purpose of namespaces? Is it good practice to keep your application in a single namespace?

5. Is the following code correct?

struct Num 
{ 
   public const double x = 1.0;
   public Num(double start)
   {
        x = start;
   }
}

6. Will the following code compile?

double d = 1.11;
int i = d;

7. What will be the output for this block of code?

int i = 5;
object b = i;
i++;
int c = ((int)b);
c++;
Console.Write(i.ToString(), b);

8. Can you describe why the lock() statement is designed to only accept reference type parameters?

9. How method arguments are passed in C#? Can this behavior be changed?

10. What is the difference between Int.Parse and Int.TryParse?

11. What are the implicit and explicit type conversions?

12. How do you cast from one reference type to another without risking to throw an exception?

13. Why isn't it possible to create an instance of an abstract class?

14. Is it possible to invoke a method from an abstract class?

15. Is it true that Interface can only contain method declarations?

16. Is it possible to specify access modifiers inside of an interface?

17. Can you inherit from two interfaces with the same method name in both of them?

18. Is it possible to define two methods with the same name and arguments, but with a different return types?

19. What is the difference between method overriding and overloading?

20. What does protected internal access modifier mean?

21. Your class Shape has one constructor with parameters. Can you create an instances of this class by calling new Shape()?

22. Is it possible to override a method which is declared without a virtual keyword?

23. What is the difference between new and override keywords in method declaration?

24. Is it possible to explicitly call a class’ static constructor?

25. How can you override a static constructor?

26. Can you use this keyword inside of a static method?

27. What is the difference between using a static class and a Singleton pattern?

28. What does immutable mean? Can you provide examples?

29. How can you create delegates in C#?

30. Are delegates of a value or a reference type?

31. What is the difference between events and multicast delegates?

32. Is there any difference between Action and Function?

33. What are lambda expressions? What are they used for?

34. Is it possible to access variables from the outside of a lambda expression?

35. What is LINQ used for?

36. What should usually be done inside of a catch statement?

37. Does the following code make sense?

try
{
     DoSomeWork();
}
catch(Exception ex){}
catch(StackOverflowException ex){}

38. What is reflection? Where can it be used?

39. What are generics?

40. What constrains can be applied to generics?

41. Can Garbage Collection be forced manually?

42. What are the generations of .NET Garbage Collector?

43. With the IDisposable interface, what logic is usually placed inside of the Dispose method?

44. Can you extend the core .NET framework class with your own method?

Lit.: Agile Principles, Patterns, and Practices in C# (Robert C. Martin, Micah Martin)

C#

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