Executing a sub

Executing a sub that takes no arguments

When you call a parameterless sub by including it in a Call statement, the sub name can end in either empty parentheses or no parentheses.

For example:

Dim aName As String
Sub PrintName1
   ' Make the contents of firstName$ be all uppercase
   ' and display the result.
   firstName$ = UCase$(firstName$)
   Print firstName$
End Sub
firstName$ = "David"
Call PrintName1()
' Output: DAVID
Call PrintName1
' Output: DAVID

You can call a parameterless sub by entering the sub name, which must not include empty parentheses.

For example:

PrintName1
' Output: DAVID

Executing a sub that takes a single argument

When you call a sub that expects a single argument, enclose the argument in parentheses when you include it in a Call statement. Enclose the argument in single parentheses to pass it by reference, or in double parentheses to pass it by value.

For example:

Sub PrintName2(someName As String)
    ' Make the contents of someName$ be all uppercase
    ' and display the result. If someName$'s contents are
    ' passed by reference, change the value of the
    ' corresponding variable in the caller's scope. 
    ' Otherwise, don't.
    someName$ = UCase$(someName$)
    Print someName$
End Sub
firstName$ = "David"
Call PrintName2(firstName$)    
' firstName$ is passed by reference by default.
' Output: DAVID
Print firstName$
' Output: DAVID
firstName$ = "David"
Call PrintName2((firstName$))
' Output: DAVID
Print firstName$
' Output: David

You can call a sub that expects a single argument by simply entering the sub's name and the argument. If you enclose the argument in parentheses, it gets passed by value to the sub. For example:

firstName$ = "David" 
PrintName2(firstName$) 
' firstName$ is passed by value.
' Output: DAVID
Print firstName$
' Output: David
PrintName2 firstName$           
' firstName$ is passed by reference.
' Output: DAVID
Print firstName$
' Output: David

Executing a sub that takes multiple arguments

When you call a sub that expects multiple arguments, enclose the arguments in parentheses when you include the sub in a Call statement, and do not enclose them in parentheses when you call the sub by simply entering its name followed by its arguments.

For example:

Dim lastName As String
Sub PrintName3(pronom As String, cognom As String)
   pronom$ = UCase$(pronom$)
   cognom$ = UCase$(cognom$)
   Print pronom$ & " " & cognom$
End Sub
firstName$ = "David"
lastName$ = "LaFontaine"
Call PrintName3(firstName$, lastName$)
Output: ' DAVID LAFONTAINE
firstName$ = "Julie"
lastName$ = "LaFontaine"
PrintName3 firstname$, lastName$
' Output: JULIE LAFONTAINE