Interview Questions and Answers

    Module Program
    Sub Main()
        Console.WriteLine("Hello, world!")
        Console.ReadLine()
    End Sub
End Module

    Imports System.Windows.Forms
    
    Module Program
        Sub Main()
            Application.Run(New MainForm())
        End Sub
    End Module
     
    
  

    Public MustInherit Class Shape
    Public MustOverride Function CalculateArea() As Double
End Class

Public Class Circle
    Inherits Shape

    Private radius As Double

    Public Sub New(radius As Double)
        Me.radius = radius
    End Sub

    Public Overrides Function CalculateArea() As Double
        Return Math.PI * radius * radius
    End Function
End Class

Public Class Rectangle
    Inherits Shape

    Private width As Double
    Private height As Double

    Public Sub New(width As Double, height As Double)
        Me.width = width
        Me.height = height
    End Sub

    Public Overrides Function CalculateArea() As Double
        Return width * height
    End Function
End Class
 
     

    // Assembly A
    namespace MyAssembly
    {
        internal class InternalClass
        {
            internal void InternalMethod()
            {
                // Internal implementation
            }
        }
    }
    
    // Assembly B
    using MyAssembly;
    
    public class AnotherClass
    {
        public void AccessInternalMember()
        {
            InternalClass obj = new InternalClass(); // Error: InternalClass is inaccessible due to its protection level
            // obj.InternalMethod(); // Error: InternalMethod is inaccessible due to its protection level
        }
    }
     
     

    Dim numbers(4) As Integer
    numbers(0) = 1
    numbers(1) = 2
    numbers(2) = 3
    numbers(3) = 4
    numbers(4) = 5
 
    ReDim Preserve numbers(7)
    numbers(5) = 6
    numbers(6) = 7
    numbers(7) = 8
     

    Dim numbers(4) As Integer
    numbers(0) = 1
    numbers(1) = 2
    numbers(2) = 3
    numbers(3) = 4
    numbers(4) = 5
 
    ReDim numbers(2)

    Dim jaggedArray As Integer()() = New Integer(2)() {}
    
    jaggedArray(0) = New Integer() {1, 2, 3}
    jaggedArray(1) = New Integer() {4, 5}
    jaggedArray(2) = New Integer() {6, 7, 8, 9}
    
    ' Accessing elements
    Console.WriteLine(jaggedArray(0)(1)) ' Output: 2
    Console.WriteLine(jaggedArray(1)(0)) ' Output: 4
    Console.WriteLine(jaggedArray(2)(3)) ' Output: 9
     

    ' Define a delegate type with a specific signature
    Delegate Function MathOperation(x As Integer, y As Integer) As Integer
    
    ' Define methods that match the delegate signature
    Function Add(x As Integer, y As Integer) As Integer
        Return x + y
    End Function
    
    Function Subtract(x As Integer, y As Integer) As Integer
        Return x - y
    End Function
    
    Sub Main()
        ' Create delegate instances and bind them to methods
        Dim operation1 As MathOperation = AddressOf Add
        Dim operation2 As MathOperation = AddressOf Subtract
    
        ' Invoke the delegate and call the associated method
        Dim result1 = operation1(5, 3) ' Calls Add(5, 3)
        Dim result2 = operation2(5, 3) ' Calls Subtract(5, 3)
    
        Console.WriteLine(result1) ' Output: 8
        Console.WriteLine(result2) ' Output: 2
    End Sub
     
     

    Imports System.Diagnostics
    
    Module Program
        Sub Main()
            ' Write a message to the default trace listener
            Trace.WriteLine("This is a trace message")
    
            ' Write an error message
            Trace.TraceError("An error occurred")
    
            ' Write a warning message
            Trace.TraceWarning("This is a warning")
    
            ' Write an informational message
            Trace.TraceInformation("This is an information message")
    
            ' Flush and close the trace listeners
            Trace.Flush()
            Trace.Close()
        End Sub
    End Module
     
    

        Dim a As Boolean = False
        Dim b As Boolean = True
        Dim result As Boolean = a And b
    

    Dim a As Boolean = False
    Dim b As Boolean = True
    Dim result As Boolean = a AndAlso b
 

    Dim str As String = "123"
    Dim intValue As Integer = Integer.Parse(str)
     
   

    Dim str As String = "123"
    Dim intValue As Integer = CInt(str)
     
 

    Dim boolValue As Boolean = True
    Dim intValue As Integer = boolValue ' Implicit conversion
    
  

    Dim boolValue As Boolean = False
    Dim intValue As Integer = Convert.ToInt32(boolValue)
     
 

    Dim boolValue As Boolean = True
    Dim intValue As Integer
 
    If boolValue Then
        intValue = 1
    Else
        intValue = 0
    End If
     

    Option Strict On
    
    Dim x As Integer = "123" ' Error: Option Strict On disallows implicit conversions
    
  

    Option Explicit On
    
    Dim x As Integer ' Variable declaration is required
    y = 10 ' Error: Variable 'y' is not declared