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Tip of the Day
Language: VB4,VB5,VB6,VBS
Expertise: beginner
Jul 29, 2000



Building the Right Environment to Support AI, Machine Learning and Deep Learning

Simplify your code with Inc and Dec functions

Unlike other languages - such as C and Delphi - VB lacks of the capability to increment and decrement a variable. Adding this feature, in the form of reusable Function routines, is simple:

Function Inc(Value As Variant, Optional Increment As Variant = 1) As Variant
    Value = Value + Increment
    Inc = Value
End Function

Function Dec(Value As Variant, Optional Decrement As Variant = 1) As Variant
    Value = Value - Decrement
    Dec = Value
End Function
The above routines declare the argument as Variant, so you can use them with any numeric data type, as in:

Dim x As Long, y As Single
' increment a Long value by one
Inc x
' increment a floating point variable by 0.1
Inc y, 0.1
You may argue whether using the Inc/Dec routines is going to make your code more or less readable. However, these functions prove to be more useful when they appear inside expressions:

' evaluate the sum of the squares of the first 100 integer numbers

' (of course, you can do this also with a For-Next loop,
'  but this is only an example)

Dim N As Long, Sum As Long

Do While N <= 100
    ' increment N, square it, and add to the Sum variable
    Inc Sum, Inc(N) ^ 2
A final note: the Inc/Dec routines are slow, at least compared with inline addition and subtraction operations. For this reason you should never use them inside time-critical loops.
John Nickle
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