HOW to pass array to sub

[margret]

Hello, I need to pass an array to a sub. I have passed variables just fine but the array is giving errors. In the sub I have tried MyVar2, MyVar(), MyVar As String and not Array. I always get an error. I want to do something like:

Dim MyVar(2,1) As String
MyVar(0,0)="Bill"
MyVar(0,1)="32"
MyVar(1,0)="Jimmy"
MyVar(1,1)="61"

MySub("ID Listing...", MyVar)


Sub MySub (Text as String, MyVar2 as Array)
     For l=0 to MyVar2.Size
          'show list
     Loop
End Sub

 

[agraham]

Try

Sub MySub (Text as String, MyVar2(,) as String)

Note the comma that indicates the rank of the passed array.

 

[kickaha]

I never knew that! Well worth an entry into the beginners section.

 

[agraham]

 

[margret]

Passing Arrays

Thank You!! Worked perfect!:sign0060:
That's the kind of stuff I need to know..!

Thanks,

Margret

 

[warwound]

Try

Sub MySub (Text as String, MyVar2(,) as String)

Note the comma that indicates the rank of the passed array.

What does 'the rank of the passed array' mean?

Thanks.

Martin.

 

[agraham]

The rank of an array is the number of dimensions it contains.

Dim one(1), two(1,2), three(1,2,3) As String

Sub test (a() AS String, b(,) As String, c(,,) As String
     ...
End Sub
    ...
    test(one, two, three)
   ...

 

[warwound]

The rank of an array is the number of dimensions it contains.

Dim one(1), two(1,2), three(1,2,3) As String

Sub test (a() AS String, b(,) As String, c(,,) As String
     ...
End Sub
    ...
    test(one, two, three)
   ...

Thanks for the info!

Martin.

 

[Erel]

I will add that the syntax for returning an array from a sub is:

Sub SubThatReturnsArray(x As Int) As String() 'returns an array of rank 1

Sub SubThatReturnsArray(x As Int) As String(,) 'returns an array of rank 2

This can be an array of any rank.

 

[enonod]

Still learning, and I think it might be useful to have more than just a solution.

Can somebody please explain why 'the system' does not know the rank of the array? After all it has been amply declared and Dim'ed up front.
The same principle seems odd to me that other declared typed variables have to be repeated when passed to Arrays.

 

[bluejay]

I agree rank should be handled by the compiler.

This syntax would also have a problem in that if you changed the Dim rank you have to modify all subs using it as a parameter even if the sub is only passing the reference to other subs.

bluejay

 

[thedesolatesoul]

Can somebody please explain why 'the system' does not know the rank of the array?

The 'system' knows the rank of the array but the 'sub' does not. After all how can the sub predict what data you want to pass to it.

After all it has been amply declared and Dim'ed up front.

The variable was declared but that has no bearing on the subroutine you want to pass it to.

 

[agraham]

The purpose of this syntax, common to many other languages, is to ensure type safety at compile time. This ensures that unexpected runtime errors do not occur through using incorrectly ranked arrays.

 

[bluejay]

I was referring to the sub call not the sub definition.

At the call the sub is given a real parameter and the compiler already knows the type of a real parameter.

bluejay

 

[bluejay]

oops! Just realised I was reading the wrong post. The syntax is already what I was suggesting.

bluejay

 

[enonod]

Thank you for the reason agraham

 

[oymyakon]

Array

Hi,
i am trying to receive an array from a java library into B4A. What is the format within B4A as i keep getting errors.

 

[Erel]

Please start a new thread for this question in the libraries developers questions. Also post the relevant code and error message.

 

[Johan Schoeman]

I am missing something here. Keep on getting an error with a difference in rank between passing and receiving. Can anyone help with this?

Sub Button3_Click
  Dim zz(6) As Double
  zz(0) = 0
  zz(1) = 90
  zz(2) = 0
  zz(3) = 30
  zz(4) = 2
  zz(5) = 0
  zz = JHSMATH.Triangle_AAS(zz)

End Sub

'the following code is in a module named JHSMATH

Public Sub Triangle_AAS (aa() As Double) as Double()

  Dim s1 As Double
  Dim s2 As Double
  Dim s3 As Double
  Dim a1 As Double
  Dim a2 As Double
  Dim a3 As Double
  s3 = aa(4)
  a1 = aa(1)
  a2 = aa(3)
  a3 = 180 - a1 - a2
  a2 = (a2/360)*2*cPI
  a1 = (a1/360)*2*cPI
  a3 = (a3/360)*2*cPI

  s2 = s3 * Sin(a3) / Sin(a1)
  s1 = s3 * Sin(a2) / Sin(a1)

  a1 = 360*a1/(2*cPI)
  a2 = 360*a2/(2*cPI)
  a3 = 360*a3/(2*cPI)

  a1 = NumberFormat2(a1,0,3,3,False)
  a2 = NumberFormat2(a2,0,3,3,False)
  a3 = NumberFormat2(a3,0,3,3,False)
  s1 = NumberFormat2(s1,0,3,3,False)
  s2 = NumberFormat2(s2,0,3,3,False)
  s3 = NumberFormat2(s3,0,3,3,False)

  aa(0) = s1
  aa(1) = a1
  aa(2) = s2
  aa(3) = a2
  aa(4) = s3
  aa(5) = a3

  Return aa


End Sub

Figured it out - made corrections to the above and it now works

 

[klaus]

What is the exact error message ?
In this code you already have an error:

Sub Button3_Click
  Dim zz(5) As Double
  zz(0) = 0
  zz(1) = 90
  zz(2) = 0
  zz(3) = 30
  zz(4) = 2
  zz(5) = 0
  zz = JHSMATH.Triangle_AAS(zz)
End Sub

You dim zz(5) which means zz(0) to zz(4) five items.
zz(5) is one element too much !