Hi all. I know this is a total noob question, but can anyone tell me why this function always returns 0:
Function Cd(Re As Double)
Select Case Re
Case Re < 1
Cd = 24 / Re
Case 1 < Re < 1000
Cd = 18 * Re ^ (-0.6)
Case 1000 < Re
Cd = 0.44
End Select
End Function
Whenever I call it in the spreadsheet, it always returns 0. For example Cd(5000) = 0, when it should be 0.44. Thanks in advance for the help.
Case Re < 1
That is not good. You evaluate Re in your Select Case in the first place, and now you are comparing Re to Re < 1. Obviously, you wanted
Case Is < 1
Case 1 < Re < 1000
That is not good either. There is no < X < operator in VB. This expression evaluates to (1 < (Re < 1000)), which essentially becomes either 1 < False or 1 < True, which is always False. What you meant to write here is:
Case 1 to 1000
Case 1000 < Re
Same problem again. You obviously meant:
Case Is > 1000
In addition to the things GSerg mentions I think you should also explicitly cast the function to return a double.
I just tested that this works as you expect:
Function Cd(Re As Double) As Double
Select Case Re
Case Is < 1
Cd = 24 / Re
Case 1 To 1000
Cd = 18 * Re ^ (-0.6)
Case Is > 1000
Cd = 0.44
End Select
End Function