As we have seen, VBA allows two kinds of procedures: functions and subroutines. As a reminder, the only difference between a function and a subroutine is that a function returns a value, whereas a subroutine does not.
A function declaration has the form:
[Public or Private] Function
Note that we must declare the data types not only of each parameter to the function, but also of the return type. Otherwise, VBA declares these items as variants.
We will discuss the optional keywords
later in this chapter, but you can
probably guess that they are used here to indicate the scope of the
function, just as they are used in variable declarations.
For example, the
AddOne function in Example 6-1 adds 1 to the original value.
Example 6-1. The AddOne Function
Public Function AddOne(Value As Integer) As Integer AddOne = Value + 1 End Function
To use the return value of a function, we just place the call to the function within the expression, in the location where we want the value. For instance, the code:
MsgBox "Adding 1 to 5 gives: " & AddOne(5)
produces the message box in Figure 6-1, where the
AddOne (5) is replaced by the return
AddOne, which, in this case, is 6.
Figure 6-1. The message dialog displayed by Example 6-1
Note that, ...