here is my problem

hi,

here is my problem.

Function t1(sita As Double, t0 As Double, l0 As Double) As Double
sita = (sita - 90) / 180 * 3.14159265
t1 = t0 - l0 * Tan(sita)
End Function 'ok

Function t2(sita As Double, t0 As Double, l0 As Double, l As Double) As
Double
t = t1(sita, t0, l0)
MsgBox sita
t2 = t + l * Tan(sita)
End Function

Sub test()
MsgBox t1(95, 7.5, 20)
MsgBox t2(95, 7.5, 20, 120)
End Sub

in MsgBox sita the sita is not 95, why.


thank you.

 

not sure what you're trying to do but my calculator gets like .087

i suggest you make another little function to do the degrees to radians or
anyway separate that from whatever else you want to do to keep it clear

i hope this helps

jm

 

thanks.

but,why it is 0.87,instead of 95.
i didnt dim sita in public,

thanks

 

hmmm
i see what you are saying
i guess if you were to use option explicit
or else just use different variable names for sita in each function
it might clear it up

JM

 

I think you are getting confused because you are passing your function parameters by reference rather than by value. To pass by value, prefix the parameter(s) with the ByVal keyword in the Function statement. When you pass parameters by reference, any modifications you make to the passed value within the function gets passed back to the original variable (in fact technically you are dealing with the *same* original variable).

So what is happening is from your test sub you are calling t2 with 95 passed in and assigned to the variable sita (note that because 95 is a literal, visual basic automatically makes this by-value). Then from within t2 you call t1 passing the variable sita which itself is assigned to a variable named sita (the fact that the names are the same is immaterial - it is the fact that it is passed by reference that is critical). Within t1 you modify the value of sita which simultaneously modifies the value of sita from t2 that you passed into t1. So by the time you exit the t1 function and display your message box within t2, the sita value has changed.

I hope this makes sense.

Regards

Wayne Ivory
IT Analyst Programmer
Wespine Industries Pty Ltd

 

Thanks for setting me straight Wayne.

JM

parameters by reference rather than by value. To pass by value, prefix the
parameter(s) with the ByVal keyword in the Function statement. When you
pass parameters by reference, any modifications you make to the passed value
within the function gets passed back to the original variable (in fact
technically you are dealing with the *same* original variable).

passed in and assigned to the variable sita (note that because 95 is a
literal, visual basic automatically makes this by-value). Then from within
t2 you call t1 passing the variable sita which itself is assigned to a
variable named sita (the fact that the names are the same is immaterial - it
is the fact that it is passed by reference that is critical). Within t1 you
modify the value of sita which simultaneously modifies the value of sita
from t2 that you passed into t1. So by the time you exit the t1 function
and display your message box within t2, the sita value has changed.