Functions and Subroutines

zaid · June 2nd, 2012, 11:52 AM

I'm reading chapter 5, till now everything is fine but I reached Functions and Subroutines and got really confused anyone please tell me what are they exactly and how they work?

Imar · June 2nd, 2012, 12:37 PM

Hi there,

As explained in the book, functions are reusable blocks of code that return something; subs are reusable blocks of code that don't return a value.

What is it you don't understand exactly?

Cheers,

Imar

zaid · June 2nd, 2012, 01:49 PM

The example in the book on page 171, for the parameters you wrote "ByVal a As Integer" but the code in the calculator has Value1 variable so how are they related?

I skipped functions and classes and started with chapter 6 but found it to be hard to follow up without a solid understanding of the previous sections.

I'm sorry if my question isn't proper or professional :p but i'm still an amateur.

Is there any link where I can get a deeper understanding.

By the way I really liked this book and recommended it on amazon just in case my post implies the opposite.

Imar · June 2nd, 2012, 02:53 PM

The a parameter is part of the definition of the function / sub (collectively referred to as methods). When you need to pass a value (called an argument) to that method, you can pass a literal value or the value of a variable (Value1, in your example).

So, a function like this:

Public Function Add (ByVal a As Integer, ByVal B As Integer) As Integer
Return a + b
End Function

can be called like this:

Dim result As Integer = myCalculator.Add(2, 4)

or like this:

Dim value1 As Integer = 2
Dim value2 As Integer = 4
Dim result As Integer = myCalculator.Add(value1, value2)

There's no relation in name between the parameters of the method, and the values you pass to it.

Maybe this helps: http://msdn.microsoft.com/en-us/libr...(v=vs.80).aspx

Cheers,

Imar