[RESOLVED] Prime number code

[Nightwalker83]

Try this:

Public Class Form1
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        
        Dim Isprime As Integer
        Dim str As String
        Dim m As Integer
        Dim n As Integer
        Dim TestLimit As String
        Dim TestPrime As String
        Dim TestNum As String
 
 
        str = ""
        m = InputBox("Enter Upper limit")
        n = InputBox("Enter lower limit")
        If (n > 50) Then
            MsgBox("outside range")
            Exit Sub
 
        End If
 
        '   
        ' Eliminate even numbers
        If TestPrime Mod 2 = 0 Then Exit Sub
        '   Loop through ODD numbers starting with 3
        TestNum = 3
        TestLimit = TestPrime
        Do While TestLimit > TestNum
          for x= TestNum to  TestLimit step 2
            If TestPrime Mod TestNum = 0 Then
                '   Uncomment this if you really want to know
                '   MsgBox "Divisible by " & TestNum   
 
                Exit Sub
            End If
 
            '   There's logic to this.  Think about it.
            TestLimit = TestPrime \ TestNum
 
            '   Remember, we only bother to check odd numbers
            TestNum = TestNum + 2
           if prime then list.additem x
             next x 
        Loop
 
        '   If we made it through the loop, the number is a prime.
 
        Isprime = True
 
 
    End Sub

I have requested the thread moved since you are using vb.net not vb6. Something such as that although, I haven't tested it so I can't be sure.