Functions and Subs

[dannyres]

Hi guys, ive been working on a project latly (im a n00b to .net) and im wondering.. what is the difference between a function and a sub... from what i can tell, a function is something that gets something and returns a value, and a sub is what does something.. could someone explain to me what is what and when to use each one?

 

 

Thanks, Dan

[Klogg]

Pretty much the only difference between the two is that a function returns a value. The last line of a function tells what value it will return, like this:

 

Return WhateverValueYouWant

Since a function returns a value, you will call it on the right side of an equals sign. That way you can assign the return value of the function to a variable. A sub procedure, however, is called by itself on its own line of code. It doesn't return a value, but just executes the code inside of it.

 

I hope this helps.

[Mothra]

You also usually declare a Function as a specific data type and Functions are normally passed some data or value to use in its process.

Public Function MyFunction(ByVal i As Integer, ByVal x As Long) As Long
    Dim n As Long
    'Some code here to do something...
    n = x * i
    Return n
End Function

Subs aren't type specific and don't always have data passed to them, although they can recieve some kind of data as a parameter. I like the way that the C languages deal with routines. ALL routines in the C's have a return type. If the routine is not required to return a value it is "void", other wise there is a data type associated with it. But, I digress. I know it's a lot more than you were asking but, for some reason I'm feeling long-winded tonight! Hope I did help a little.

[dannyres]

Ok i think ive got it now :)

 

 

Thanks, Dan

 

EDIT: is it bad coding practice to have a function that doesnt return anything?

[Mehyar]

Yes ofcourse ....

[mutant]

EDIT: is it bad coding practice to have a function that doesnt return anything?

That will cause a compiler error if you have Option Strict On, which you should have.