Question

I’m writing some code in Visual Basic 6 and I have noticed that I don’t even need to declare variables for things to work.

The following (explicit declaration):

Dim foo As String
foo = "Bar"

Seems to work just as well as this (implicit declaration):

Dim foo
foo = "Bar"

Or this (no declaration):

foo = "Bar"

I know in C# I need to declare a variable before I use it, and that implicit and explicit declarations are both acceptable. I also know that in Python, you don’t declare your variables at all before you use them.

In regards to Visual Basic 6 (and by extension VBA) which is proper?

Thanks

Answer 1

Should I explicitly declare my variables in VB6?

Yes. Why?

Not just because it is a good habit or it is a must but because of only one main reason which I have mentioned in this post as well.

VB defaults the variable to being type Variant. A Variant type
variable can hold any kind of data from strings, to integers, to long
integers, to dates, to currency etc. By default “Variants” are the
“slowest” type of variables.

AND

As I mentioned earlier, If you do not specify the type of the
variable, VB defaults the variable to being type Variant. And you
wouldn’t want that as it would slow down your code as the VB Compiler
takes time to decide on what kind of variable you are using. Variants
should also be avoided as they are responsible for causing possible
“Type Mismatch Errors”.

Topic: To ‘Err’ is Human (See Point 3)

Link: http://siddharthrout.wordpress.com/2011/08/01/to-err-is-human/

The above link also covers other parts related to coding that one can/should take care of.

HTH