[2008] Randomness and arrays

[RILEY343]

Im making a random cipher generator and here's what it looks like:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

This pattern is repeated for the lower case letters, numbers (0-9), and symbols (< > # ...). I all ready have this:

Public Class NcryptKeyGen
    Dim strStatic(92) As String
    Dim strDynamic(92) As String
    Dim Y As Integer = 93

    Public Function X() As Integer
        Randomize()
        X = Int(Rnd() * Y)

        MsgBox(Y)
    End Function
    Private Sub btnGO_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGO.Click
        MsgBox("Generating code...")

        lblGTp.Text = strStatic(X())
        Y = Y - 1
        lblLTp.Text = strStatic(X())
        Y = Y - 1
    End Sub

The arrays are way too long to post...but they're there. The reason that Y=Y-1 is so that the maximum parameter goes down one each time the function occurs. What i need to do to, is ensure that this remains a function where one value is assigned to one value so that i do not end up with A = @ and A = %. To do this, i believe that i need to delete the value i used to set the text property of a label.

So, when % is assigned to A (at random), % will no longer be chosen and deleted...which is why the max parameter of the number generator is moved down one each cycle. So, how would i delete the just used element from an array during run time and after the Public Function X() is executed? i would appreciate any help with this matter.

[jmcilhinney]

First up, don't use Randomize and Rnd to generate random numbers. Create a Random object and then call its Next method.

As for the question, see this CodeBank thread of mine.

[RILEY343]

I don know how to use the code you gave me. Im looking over it and i thing i can make it work but my main question is how to i change it around so that it chooses between 93 different characters?

[jmcilhinney]

You're making a common mistake of looking just at the code rather than considering what the code does in a general sense. That code takes all the potential values and adds them to a collection. It then removes each value from that collection as it's used, so it can't be used again. That's all you have to do.

You're using Char values rather than Integers so you simply create a List(Of Char) and call AddRange to add the contents of the array you already have. Then, when you generate a random number you use it to index the collection instead of the array. You then call RemoveAt to remove that item from the collection so it cannot be used again. If you do generate the same random number again it will be the index of a different Char.

[RILEY343]

How does this look: (I've probably made some silly mistake somewhere)

   1.
      Dim list As New ArrayList

              For i As String = 0 To 92
                  list.Add(i)
              Next i

              Dim rand As New Random
              Dim index As Integer
              Dim item As Object

              While list.Count < 0                  
                  index = rand.Next(0, list.Count)

                  item = list(index)
 
                  list.RemoveAt(index)
 
              End While

In the mean time...im going to test it on a scrap program.

Edit: Its wrong. played around with it for a while....wouldnt stop returning the first index's value...0. I changed 0 to zero to make sure it was the first index and not some totally weird mistake.