Help with vba function

[TheAaron]

Hello, I have the following function:

Function Fun(z)
Fun = z - x - (((((z - Dato1) * Dato1P) + Dato3) - (((((z - Dato1) * Dato1P) * Dato2) + Dato4) * R)) - Dato5)
End Function

There are several varibles within it, the thing is that it just does not work, for example:
Fun(20) returns 20

What can I do?

 

[NdNoviceHlp]

Fun(Z) = 20 because only "z" has a value in your formula... 20 - nothing = 20 If your variables(x, Dato1, Dato2, etc.) have any values(?) they need to be scoped/declared so as to allow your function to use them. Public Dim then in module code if necessary. HTH. Dave
ps. Perhaps your function should also be module code and declared as...

Public Function Fun(z as Double) as Double

... great name for a FUNction!

 

[StephenCrump]

What can I do?

Perhaps start by telling us what your function is meant to do, and what are x, Dato1, Dato1P, Dato2 etc?

Unless you have declared your variables at module level and given them a value elsewhere, they will all have value zero inside your function. So your function simplifies to:

Fun = z - 0 - (((((z - 0) * 0) + 0) - (((((z - 0) * 0) * 0) + 0) * 0)) - 0)
= z

So Fun(20)= 20

Presumably you mean to pass the variables as arguments for the function, in the same way you have with z?

I also recommend using Option Explicit in each of your code modules. Then the compiler will give you the more helpful message "Variable not defined".

 

[ww4612]

Function Fun(byval z as integer, x as integer, Dato1 as integer,Dato2 as integer, Dato3 as integer, Dato4 as integer, Dato1P as integer, r as integer) as integer
Fun = z - x - (((((z - Dato1) * Dato1P) + Dato3) - (((((z - Dato1) * Dato1P) * Dato2) + Dato4) * R)) - Dato4)
End Function

try this
fun(1,2,3,4,5,6,7,8)=1 - 2 - (((((1 - 3) * 7) + 5) - (((((1 - 3) * 7) * 4) + 6) * 8)) - 6)=-386

 

[TheAaron]

Thanks to all!
My variables are defined later on my module, I'll see what I cand do with you tips.