Here is a simple tutorial to help pick six non-repeating numbers or any non-repeating elements you want to use. i.e. the Alphabet.
As always we start with the Dim statements



There are only two controls needed on the form one is a Button and the other is a Label.
In the Buttons Event Procedure.is where all the code is placed to pick the random numbers and display the results in the Label.
First make sure that the Label is empty.



Now we need to set up a For / Next Loop to hold six numbers,



So, our For / Next Loop will go around six times, but without some more code it will not be very interesting.

What follows next is the code that will do the magic.
You will notice that inside our For / Next x Loop we have a nested For / Next y Loop.
This is the Loop that checks if the Random number has already been picked.
How? Well, first the random number is checked to see if it exists in our arrNumber(y), remember the tutorials on Arrays? So it looks at the first place in the array which first time the loop is entered is (0) in fact this is what the array looks like to start with.
arrNumber(0) = 0
arrNumber(1) = 0
etc
arrNumber(5) = 0
After the y Loop has finished and no numbers in the arrNumber have been found it moves on to the last bit of code inside the x For / Next Loop so that we get, assuming our first Random Number was 19 the following
arrNumber(0) = 19 once this is done off it goes again
First y Loops to see if the second Random Number has been already been picked.
Array y now looks like this
arrNumber(0) = 19
arrNumber(1) = 0
etc
arrNumber(5) = 0

If the second Random Number is 38 then as it Loops through the y Array it will not find 38, so it moves on and places 38 in the x Array (Not Medical!)
Off it goes again this time let’s say the Random Number is 19 again, as the y Loop is performed it finds 19 in arrNumber (0) position so now it uses GoTo and jumps up to Start: where it picks another Random Number to try, it keeps doing this until all six places in the Array are filled with Non-Repeating Numbers.
See the code below.



The last stage is to place the numbers in to the Label



The full code is here for you to Copy (Ctrl+C) and Paste (Ctrl+V)

Nice tutorial, well presented. However, the goto command is a bit old-school and frowned upon by many nowadays.

Not working for me, are you sure you created this in VB or VB6?

This post has been edited by westmatrix99: 29 Sep, 2007 - 02:52 PM

I think its .net

Yes this is .NET

"Label1.Text" = VB.NET

"Label1.Caption" = VB6

A better algorithm is to place all the possible picks into a collection. Then randomly choose an index in the collection to make a selection. Then remove that item from the collection so that it cannot be selected again. This means it won't need to repeatedly try to pick an item it hasn't selected before.

Module Module1

    Private rand As New Random

    Sub Main()
        ' Store the numbers 1 to 6 in a list '
        Dim allNumbers As New List(Of Integer)(Enumerable.Range(1, 6))
        ' Store the randomly selected numbers in this list: '
        Dim selectedNumbers As New List(Of Integer)
        For i As Integer = 0 To 5
            ' A random index in numbers '
            Dim index As Integer = rand.Next(0, allNumbers.Count)
            ' Copy the item at index from allNumbers. '
            Dim selectedNumber As Integer = allNumbers(index)
            ' And store it in our list of picked numbers. '
            selectedNumbers.Add(selectedNumber)
            ' Remove the item from the list so that it cannot be picked again. '
            allNumbers.RemoveAt(index)
        Next
        ' Show them on the command line '
        For Each i As Integer In selectedNumbers
            Console.WriteLine(i)
        Next
    End Sub

End Module