Even and Odd

[Patrickh]

Still using VB.
sorry C# guys
dad got me a book

so i made a random number generator where you put down 2 values in text boxes and it generates a number between them (when you hit cmdGenerate)

then I wanted to add options for evens only and odds only, but I don't know how. here's what I have, I just need to know how to make it so the generated # is even for the first case, and odd for the second case

Code: Select all

 Private Sub cmdGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGenerate.Click
        If IsNumeric(TextBox1.Text) And IsNumeric(TextBox2.Text) Then
            Select Case True
                Case optEven.Checked
                    Dim objRandom As System.Random
                    objRandom = New Random(Now.Millisecond)
                    lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text)
                Case optOdd.Checked
                    Dim objRandom As System.Random
                    objRandom = New Random(Now.Millisecond)
                    lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text)
                Case Else
                    Dim objRandom As System.Random
                    objRandom = New Random(Now.Millisecond)
                    lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text)
            End Select
        Else
            MsgBox("Not a number, idiot.", MsgBoxStyle.Exclamation, "Error")
        End If


    End Sub

thanks

[xbox7887]

For an even case, do a logical AND of the number by 0xFFFFFFFE and for an odd case do a logical OR by 1.

[Patrickh]

For an even case, do a logical AND of the number by 0xFFFFFFFE and for an odd case do a logical OR by 1.

thanks for helping me, but can you be a bit more specific? I'm new to programming. Are you saying I need to do an And/Or statement?

[xbox7887]

I've never used visual basic before but I believe they spell out their stuff so I would try something along the lines of...

Code: Select all

int number = Random().Next();
int evenNumber = number AND 0xFFFFFFFE;
int oddNumber = number OR 1;

Also when referencing hexidecimal, they may use a different format like 0FFFFFFFEH...you should be able to figure it out from there. And pay no attention to my C-style variable declarations, use the Dim bullshit that VB makes you do

[LuxuriousMeat]

Use this:

Code: Select all

Private Sub cmdGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGenerate.Click
        If IsNumeric(TextBox1.Text) And IsNumeric(TextBox2.Text) Then
           Select Case True
            Case optEven.Checked
                Dim objRandom As System.Random
                objRandom = New Random(Now.Millisecond)
                lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text) And Integer.Parse("FFFFFFFE", Globalization.NumberStyles.HexNumber)
            Case optOdd.Checked
                Dim objRandom As System.Random
                objRandom = New Random(Now.Millisecond)
                lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text) Or 1
            Case Else
                Dim objRandom As System.Random
                objRandom = New Random(Now.Millisecond)
                lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text)
        End Select
        Else
            MsgBox("Not a number, idiot.", MsgBoxStyle.Exclamation, "Error")
        End If


    End Sub

[Patrickh]

Use this:

Code: Select all

Private Sub cmdGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGenerate.Click
        If IsNumeric(TextBox1.Text) And IsNumeric(TextBox2.Text) Then
           Select Case True
            Case optEven.Checked
                Dim objRandom As System.Random
                objRandom = New Random(Now.Millisecond)
                lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text) And Integer.Parse("FFFFFFFE", Globalization.NumberStyles.HexNumber)
            Case optOdd.Checked
                Dim objRandom As System.Random
                objRandom = New Random(Now.Millisecond)
                lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text) Or 1
            Case Else
                Dim objRandom As System.Random
                objRandom = New Random(Now.Millisecond)
                lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text)
        End Select
        Else
            MsgBox("Not a number, idiot.", MsgBoxStyle.Exclamation, "Error")
        End If


    End Sub

that worked, thanks!

[Prey]

Seeing as the 'Random' class is always used you might as well declare that at the start, and you might as well make the hex conversion more "vb"-ish too.

Code: Select all

If IsNumeric(TextBox1.Text) And IsNumeric(TextBox2.Text) Then

    Dim objRandom = New Random()

    Select Case True
        Case optEven.Checked
            lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text) And Val("&HFFFFFFFE")

        Case optOdd.Checked
            lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text) Or 1

        Case Else
            lblRandomNumber.Text = objRandom.Next(TextBox1.Text, TextBox2.Text)
    End Select

Else
    MsgBox("Not a number, idiot.", MsgBoxStyle.Exclamation, "Error")

End If

[Patrickh]

Thanks prey. One small problem, I was playing with the program and I entered 3 and 5, then checked the evens box. It spit out 4s and 2s

does anyone know why this is? or possible solutions?
and yes, it does it every time, I closed the app and tried again with the same results
(yes the evens box is checked, but it's under more options

[xbox7887]

Because you're still running your even odd code...if it randomly generates a 3 (which is your min), then the even code will lop off the ones bit and make it a two...

Basically, you get a random number...if you want it odd the code rounds up, if you want it even the code rounds down ;p

[Prey]

You could put in a few while statements then that'll keep looping until the number is within its boundaries,

Code: Select all

If IsNumeric(TextBox1.Text) And IsNumeric(TextBox2.Text) Then

    'first we run a few tests to make sure there is at least a gap of two
    Dim varDiff As Integer = TextBox2.Text - TextBox1.Text
    If varDiff = 0 Or varDiff = 1 Or varDiff = -1 Then End

    'If we're still here then yes there is an 'in-between'. Without those 
    'tests the while loops could have potentially looped on forever

    'Declare
    Dim objRandom = New Random()
    Dim varRandom As Integer = TextBox1.Text - 1

    'Get random integer
    Select Case True

        Case optEven.Checked
            'If the var is smaller or equal to textbox1's text, or the var
            'is bigger than or equal to textbox2's text; continue looping
            While varRandom <= TextBox1.Text Or varRandom >= TextBox2.Text
                varRandom = objRandom.Next(TextBox1.Text, TextBox2.Text) And Val("&HFFFFFFFE")
            End While

        Case optOdd.Checked
            While varRandom <= TextBox1.Text Or varRandom >= TextBox2.Text
                varRandom = objRandom.Next(TextBox1.Text, TextBox2.Text) Or 1
            End While

        Case Else
            varRandom = objRandom.Next(TextBox1.Text, TextBox2.Text)

    End Select

    'Display
    lblRandomNumber.Text = varRandom

Else
    'Error handling
    lblRandomNumber.Text = "Not a number, idiot."

End If

[OwnZ joO]

Another way to determine if a number is even or odd is to divide it by 2 and if the remainder is 0 then it's even

I'm really not sure on my vb.net code anymore, but i think it would look something like this just for determining if it's even:

Code: Select all

Private Function IsEven(byval number As Integer)As Boolean
  int rem = number mod 2 ' mod returns the remainder of division
  return rem = 0 ' if it's remainder is 0 return true, else false
End Function

[Patrickh]

Wow, you guys are really helpful!
Here is the solution I came up with, it fixes the problem fine, but let me know if this is bad practice or something. All I did was add this:

Code: Select all

If CInt(lblRandomNumber.Text) < CInt(TextBox1.Text) Then
            cmdGenerate.PerformClick()
        End If

That way if the number isn't equal to or above the min value, it tries again, and so on, until it generates a proper number

[Prey]

Wow, you guys are really helpful!
Here is the solution I came up with, it fixes the problem fine, but let me know if this is bad practice or something. All I did was add this:

Code: Select all

If CInt(lblRandomNumber.Text) < CInt(TextBox1.Text) Then
            cmdGenerate.PerformClick()
        End If

That way if the number isn't equal to or above the min value, it tries again, and so on, until it generates a proper number

Yea ok, but that doesn't take into account if the number is bigger than TextBox2. Also you shouldn't have to 'CInt', vB should take care of that for you. One last thing, is that code in the 'cmdGenerate.PerformClick()' method? Because otherwise the number returned could again be outside the boundaries and you wouldn't have any to code left to check again.

[Patrickh]

Wow, you guys are really helpful!
Here is the solution I came up with, it fixes the problem fine, but let me know if this is bad practice or something. All I did was add this:

Code: Select all

If CInt(lblRandomNumber.Text) < CInt(TextBox1.Text) Then
            cmdGenerate.PerformClick()
        End If

That way if the number isn't equal to or above the min value, it tries again, and so on, until it generates a proper number

Yea ok, but that doesn't take into account if the number is bigger than TextBox2. Also you shouldn't have to 'CInt', vB should take care of that for you. One last thing, is that code in the 'cmdGenerate.PerformClick()' method? Because otherwise the number returned could again be outside the boundaries and you wouldn't have any to code left to check again.

Yes it is the last thing inside the click event, so if the number is less than the min it just tries again. as for the greater than textbox2, now that i think about it i should add that, because if you asked for an odd number between 2 and 4 it would give you five. good call