Microsoft Office Tutorials and References
In Depth Information
Chapter 6. Functions and Subroutines
Chapter 6. Functions and Subroutines
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.
6.1 Calling Functions
A function declaration has the form:
[Public or Private] Function FunctionName Param1 As DataType1 , _ (
Param2 As DataType2 ,...) As ReturnType
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 Public and Private 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 expression AddOne (5) is replaced by the
return value of AddOne , which, in this case, is 6.
Figure 6-1. The message dialog displayed by Example 6-1
Note that, in general, any parameters to a function must be enclosed in parentheses within the
function call.
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