Functions v Procedures

[confusion123]

The main (possibly only) difference between a function and a procedure is a function can return values whereas procedures can't.

Therefore why use procedures at all? Why not just write functions and return values if you want, don't if you don't need to?

 

[RoryA]

Why write a function that doesn't return a value? Why not distinguish between routines that do/don't return values? In what way would it be better not to?

 

[confusion123]

Just thought of simplifying matters, ie if functions do everything procs do and more, you only need to learn 1 thing instead of 2.

 

[RoryA]

Well, it's your code, so you can write it however you like.

 

[Peter_SSs]

The main (possibly only) difference between a function and a procedure is a function can return values whereas procedures can't.

Where did that 'fact' come from?
Could you write a function to ..
- add a worksheet to a workbook?
- delete column J?
- put borders around each cell in the range B5:D8?
- open all the excel files in a folder and put a 1 in cell A1 of the first worksheet?
- etc

 

[thisoldman]

Short answer, it's language design.

An excel sub can be executed directly, a function can only be called by another procedure or as a User Defined Function. Try writing a function to delete rows that you can call with a keyboard shortcut.

Some scripting languages only have functions: everything returns a value.

 

[Legacy 143009]

In fact, you've given your own answer. You can relatively consider functions like custom "Method"s.
Think you need a custom check like "if a boolean array contains a true value". There is no such standard method to check this as far as I know.

So there are two ways to do it:
Procedural Way

Sub Procedure (
Boolean check = False
For Each i as Boolean In B[]
If B(i) is True Then
check = True
End If
Next
If check is True Then 
'Do something
End If
)

With Function

Function checkArrayContainsTrue(ByRef array[]) As Boolean (
For Each i as Boolean In B[]
If B(i) is True Then
Return True
End If
Next
)

Sub Procedure (
If checkArrayContainsTrue(B[]) Then 
'Do something
End If
)

.
Sorry for my syntax. I have been dealing with C++ for a long time and forgot some of the correct VB notation but i guess, you've got the idea.
If you use only procedural statements you have to write this kind of a check in every sub procedure. But if it is defined once in a function, then, you can call it anywhere, anytime as you like. A more celan way let's say. Also in a long term it may lead you to learn Object Oriented Programming.

 

[RoryA]

Where did that 'fact' come from?
Could you write a function to ..
- add a worksheet to a workbook?
- delete column J?
- put borders around each cell in the range B5:D8?
- open all the excel files in a folder and put a 1 in cell A1 of the first worksheet?
- etc

Yes, very easily! Write a subroutine to do it then change the word Sub to Function.

 

[RoryA]

a function can only be called by another procedure or as a User Defined Function

That's not entirely true. Functions can be run from the macros dialog (you have to type the name in yourself) and assigned to shapes.

 

[Peter_SSs]

Yes, very easily! Write a subroutine to do it then change the word Sub to Function.

What would call the function?