Confused? How to find even numbers between two numbers? VB.NET - vb.net

Question

How do I find the even numbers from 6 through 16.
The thing is I'm working with events. How should I do this? I did a lot of research and found some code that might work but I'm not sure how it works. (I'm by no means advanced with vb.net - I'm just trying to finish this course.)
What I did find was that I have to use MOD? I'm not even really sure how to use that with an event? Any code would be awesome to getting me on the road to finish this assignment.
I took this code out of a program that had to find even numbers and it works great but the only downfall is that it starts from 1 and then whatever number you want it to stop at. I only need 6 through 16 ..
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Diagnostics
Module Module1
Private Delegate Sub numManip()
Sub Main()
Dim evennumber As numManip
Dim allNumbers As [Delegate]
evennumber = New numManip(AddressOf Even)
allNumbers = [Delegate].Combine(evennumber)
allNumbers.DynamicInvoke()
End Sub
Sub Even()
Console.Clear()
Dim counter As Integer = 2
Console.WriteLine("Even Numbers")
Console.WriteLine("Please Enter the Number you Wish to End at: ")
Dim number As Integer = Console.ReadLine()
Console.Clear()
Console.WriteLine("All Even Numbers From 6 to " & number)
Do Until counter > number
Console.WriteLine(counter)
counter += 2
Loop
Console.WriteLine("Press Enter to Continue...")
Console.ReadLine()
End Sub
Public Enum Numbers
Unset
Prime
Composite
End Enum
End Module

Answer 1

This code would work great for you.. You just need to change the logic a little. This code start at 2, since counter is 2. You can of course change that number to start at whatever you want using the same logic as you enter the last number (if you can enter the last, you can of course enter the first ;) ).
The other thing you have to change, is to use the mod operator to get the remainder of the division, since when you start at an add number, you will have problem is you always assume that your first number is even...
anyway.. if you want to start at 6, just change this line
Dim counter As Integer = 2
to
Dim counter As Integer = 6
and if you always want to finish at 16 just change this
Console.WriteLine("Even Numbers")
Console.WriteLine("Please Enter the Number you Wish to End at: ")
Dim number As Integer = Console.ReadLine()
Console.Clear()
to this:
Dim number As Integer = 16

Answer 2

Why do you say you are using events? First of all, none of the code you showed uses events, but even if your code to calculate the numbers was in an event handler, it wouldn't change anything. If however, your code needs to raise events each time it finds an even number, or raises an event when it's done, that changes things a little.
Everything you are doing in the Main method is pointless. All it accomplishes is to call the Even method, which you could do very simply like this:
Sub Main()
Even()
End Sub
Even if you needed to use a delegate for some reason, which there doesn't appear to be any reason why you do, all you would have to do is something like this:
Sub Main()
Dim evenDelegate As numManip = New numManip(AddressOf Even)
evenDelegate.Invoke()
End Sub
In your Even method, I would use a For loop, not a Do Loop. If you find the first even number, you could step by 2, such as
For i As Integer = evenStartingNumber To endingNumber Step 2
Next
Otherwise, you need to loop through every number (stepping by 1), and then test each number to see if it's even or odd. Such as:
For i As Integer = startingNumber To endingNumber
If IsEven(i) Then
End If
Next
To determine if a number is even or odd, that's where the Mod operator comes in. Mod returns the remainder from a division operation (the left over fraction). So for instance, 10 divided by 4 is 2 with a remainder of 2. When you divide any even number by 2, the remainder is always zero, so if x Mod 2 = 0, then x is an even number.

Answer 3

Without diving in to the other parts of the assignment, you check for even numbers using 'Mod 2'
If (myNum Mod 2) = 0 Then
'It's even!
Else
'It's not!
End If
For the Events part of it: I don't want to give you code to cut and paste, but consider this idea: your main sub iterates through the number 6..16. On each number, you raise a custom event. Inside the event you output to the console if its even.
Class NumEventArgs
Inherits EventArgs
Public Property Num() As String
Public Sub New(num As Integer)
Me.Num = num
End Sub
End Class
Public Event NumCheckEvent(sender As Object, e As NumEventArgs)
Sub Main()
AddHandler NumCheckEvent, AddressOf NumCheckEventHandler
For i = 6 To 16 Step 2
RaiseEvent NumCheckEvent(Nothing, New NumEventArgs(i))
Next
End Sub
Sub NumCheckEventHandler(sender As Object, e As NumEventArgs)
If e.Num Mod 2 = 0 Then
Console.WriteLine("Even!")
End If
End Sub