VBA/Excel/Access/Word/Language Basics/Optional Arguments

Using Optional Arguments

 
Function Avg(num1, num2, Optional num3)
    Dim totalNums As Integer
    totalNums = 3
    If IsMissing(num3) Then
        num3 = 0
        totalNums = totalNums - 1
    End If
    Avg = (num1 + num2 + num3) / totalNums
End Function
Sub avgSub()
    MsgBox Avg(2, 3)
    MsgBox Avg(2, 3, 5)
End Sub