Programming Forums > Application Development > Visual Basic

Johnny_English · Sep 22nd, 2004, 9:48 AM

Hello,
I'm a beginner in VB and I'm having trouble with my code. It's a prime number calculator. Here is the function:

Public Function prime(x As Integer)
  Dim primes(0) As Integer
  primes(0) = 2
  For y = 2 To x
    bound= UBound(primes)
    For Index = 0 To bound
      If (y Mod primes(Index)) = 0 Then
        Exit For
      End If
    Next Index
    If Index = bound Then
        ReDim Preserve primes(boun + 1)
        primes(bound + 1) = y
    End If
  Next y
End Function

It receives the argument x passed by main.

When I run the code I get "Array already dimentioned."

Infinite Recursion · Sep 22nd, 2004, 10:09 AM

Some of your variables are misspelled, others are undefined... I don't have VB on hand right now, but try this:

(Toggle Plain Text)

Public Function prime(ByVal x As Integer)
    Dim primes(0) As Integer
    Dim bound, y, Index As Integer

    primes(0) = 2
    For y = 2 To x
      bound = UBound(primes)
      For Index = 0 To bound
        If (y Mod primes(Index)) = 0 Then
          Exit For
        End If
      Next Index
      If Index = bound Then
        ReDim Preserve primes(bound + 1)
        primes(bound + 1) = y
      End If
    Next y
  End Function

Berto · Sep 22nd, 2004, 10:09 AM

edit: ignore what i wrote if you read it.

Infinite Recursion · Sep 22nd, 2004, 10:38 AM

it was pretty good advice too Berto.

The code above compiles and runs fine in VB .NET

Berto · Sep 22nd, 2004, 10:41 AM

nah i said something that was wrong, by a mile so thought i should get rid of it.

Ooble · Sep 22nd, 2004, 11:15 AM

In VB (not sure about VB .NET, but as you're not using that, it's irrelevant), if you want to redimension an array, you have to define it without any dimensions:

(Toggle Plain Text)

Dim primes() as Integer

Then redimension it at the start.

Sep 22nd, 2004, 9:48 AM	#1
Johnny_English Newbie Join Date: Sep 2004 Posts: 7 Rep Power: 0	Hello, I'm a beginner in VB and I'm having trouble with my code. It's a prime number calculator. Here is the function: (Toggle Plain Text) Public Function prime(x As Integer) Dim primes(0) As Integer primes(0) = 2 For y = 2 To x bound= UBound(primes) For Index = 0 To bound If (y Mod primes(Index)) = 0 Then Exit For End If Next Index If Index = bound Then ReDim Preserve primes(boun + 1) primes(bound + 1) = y End If Next y End Function Public Function prime(x As Integer) Dim primes(0) As Integer primes(0) = 2 For y = 2 To x bound= UBound(primes) For Index = 0 To bound If (y Mod primes(Index)) = 0 Then Exit For End If Next Index If Index = bound Then ReDim Preserve primes(boun + 1) primes(bound + 1) = y End If Next y End Function It receives the argument x passed by main. When I run the code I get "Array already dimentioned."

Sep 22nd, 2004, 10:09 AM	#2
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	Some of your variables are misspelled, others are undefined... I don't have VB on hand right now, but try this: (Toggle Plain Text) Public Function prime(ByVal x As Integer) Dim primes(0) As Integer Dim bound, y, Index As Integer primes(0) = 2 For y = 2 To x bound = UBound(primes) For Index = 0 To bound If (y Mod primes(Index)) = 0 Then Exit For End If Next Index If Index = bound Then ReDim Preserve primes(bound + 1) primes(bound + 1) = y End If Next y End Function Public Function prime(ByVal x As Integer) Dim primes(0) As Integer Dim bound, y, Index As Integer primes(0) = 2 For y = 2 To x bound = UBound(primes) For Index = 0 To bound If (y Mod primes(Index)) = 0 Then Exit For End If Next Index If Index = bound Then ReDim Preserve primes(bound + 1) primes(bound + 1) = y End If Next y End Function __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Sep 22nd, 2004, 10:09 AM	#3
Berto Programming Guru Join Date: Aug 2004 Posts: 1,022 Rep Power: 6	edit: ignore what i wrote if you read it. __________________ "Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT'S relativity." - Albert Einstein

Sep 22nd, 2004, 10:38 AM	#4
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	it was pretty good advice too Berto. The code above compiles and runs fine in VB .NET __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Sep 22nd, 2004, 10:41 AM	#5
Berto Programming Guru Join Date: Aug 2004 Posts: 1,022 Rep Power: 6	nah i said something that was wrong, by a mile so thought i should get rid of it. __________________ "Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT'S relativity." - Albert Einstein

Sep 22nd, 2004, 11:15 AM	#6
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	In VB (not sure about VB .NET, but as you're not using that, it's irrelevant), if you want to redimension an array, you have to define it without any dimensions: (Toggle Plain Text) Dim primes() as Integer Dim primes() as Integer Then redimension it at the start. __________________ Me :: You :: Them

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Programming Forums > Application Development > Visual Basic

Redim Problem