Imports System

Public Module Module1

    Public Sub Main()

        ' Prime Number Tester using a DO…WHILE loop

​

        ' Declare variables

        Dim Number, Modulus, LoopCounter As Integer

        Dim NumFactors As Integer = 0

​

​

        ' Prompt and accept user input

        Console.WriteLine("Enter number to test")

        Number = Console.ReadLine()

​

        ' Set up a DO…WHILE loop to count how many factors the number has

       LoopCounter = 1 

       Do While LoopCounter <= Number

              ' Find the remainder when number is divided by current loop counter

              Modulus = Number Mod LoopCounter

              ' If modulus is 0, the loop counter value must be a factor

              If Modulus = 0 Then

                   ' Increment number of factors by 1

                   NumFactors = NumFactors + 1

              End If

              LoopCounter = LoopCounter + 1

        Loop

​

        ' The number is prime if there are 2 and only 2 factors

        If NumFactors = 2 Then

               Console.WriteLine("PRIME")

        Else

               Console.WriteLine("NOT PRIME")

        End If

​

​

    End Sub

End Module