vb.net factorial

[Chan Smith]

I need to write a programing in visual basic .net to calculate the factorial of a number using a do loop. Anyone know how?

a factorial is 4 * 3 * 2 * 1 = 24

factorial of 4

[Winston]

   Function calculateFactorial(ByVal number As Integer) As Double
        Dim factorial As Double = 1.0
        For i As Double = 1.0 To number
            factorial = factorial * i
        Next
        Return factorial
    End Function


    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        MessageBox.Show(Me.calculateFactorial(4))
    End Sub

[John Veteran]

You don't need to use doubles :huh: Integers work fine; if you're using large numbers, use longs (System.Int64, I forget what VB calls them) (Y)

But otherwise, Winston's code is right :yes:

[Winston]

  gameguy said:

You don't need to use doubles :huh: Integers work fine; if you're using large numbers, use longs (System.Int64, I forget what VB calls them) (Y)

But otherwise, Winston's code is right :yes:

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I wasn't too sure, i had to use doubles, i tested it out inside the normal windows calc and put in say 90!, and it gave a double back, so i just used double and it works fine, so meh :)

[John Veteran]

  Winston said:

I wasn't too sure, i had to use doubles, i tested it out inside the normal windows calc and put in say 90!, and it gave a double back, so i just used double and it works fine, so meh :)

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Well the factorial of 90 is an absolutely enormous number, so what do you expect? :p

[snippet1]

  gameguy said:

Well the factorial of 90 is an absolutely enormous number, so what do you expect? :p

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But we hvae to consider strangely large numbers for the user!

[John Veteran]

That's a job better left for validation :yes:

[Sn1p3t]

Use Longs instead. Factorials are always going to be integer values, but I think Longs can hold larger values than Doubles (and of course I'm having problems finding that info on Google :p)