A magic number is a number that comes out of nowhere, and is directly used in a statement. Magic numbers are often used, for instance to limit the number of iterations of a loops, to test the value of a property, etc.


Using magic numbers may seem obvious and straightforward when you're writing a piece of code, but they are much less obvious and straightforward at debugging time.


That is why magic numbers must be demystified by first being assigned to clearly named constants before being used.

== Noncompliant Code Example

----
Class Foo
  Sub DoSomething(Param As Integer)
    If Param > 100 Then ' Magic Number
      ' Do something
    End If
  End Sub
End Class
----

== Compliant Solution

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Class Foo
  Private Const MaxOfSomething As Integer = 100

  Sub DoSomething(Param As Integer)
    If Param > MaxOfSomething Then
      ' Do something
    End If
  End Sub
End Class
----
