Factorial sub

[anish201]

I am trying to write a sub to get the factorial of a number. From the code below, can someone tell me why I need to have the fac = 1 line before the For Next loop?

Sub factorial()
    Dim fac As Integer, i As Integer, Num As Integer
Num = Range("a1").Value
fac = 1
    For i = 1 To Num
    fac = i * fac
    Next i
Range("a2").Value = fac
End Sub

[TonyJollans]

Because the uninitialised value of an integer is zero.

[Bob Phillips]

I am trying to write a sub to get the factorial of a number.

Why do you have the need for this sub, Excel has a Fact worksheet function

=FACT(5)

If you want to do many in a batch, it would still be more efficient to call the worksheet function from VBA

Sub factorial()
Range("a2").Value = Application.Fact(Range("a1").Value)
End Sub

simpler and more efficient

[Zack Barresse]

anish201 - [uvba]here ya go[/uvba]

Also, guess I'll add my pence worth, as a Boolean UDF ...

Function ISFACTOR(lNum As Long, lFact As Long) As Boolean
   ISFACTOR = Not CBool(lNum Mod lFact)
End Function