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How many CASE in a DO CASE ?
Message
 
À
23/05/2007 10:00:02
Hilmar Zonneveld
Independent Consultant
Cochabamba, Bolivie
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Versions des environnements
Visual FoxPro:
VFP 9 SP1
OS:
Windows XP SP2
Divers
Thread ID:
01227909
Message ID:
01227913
Vues:
18
>>What is the limit of CASE in a DO CASE ?
>
>I don't think there is one.
>
>But for practical reasons, please consider the following example:
>
>
>do case
>case x = 1
>  ...
>case x = 2
>  ...
>case x = 3
>  ...
>...
>case x = 500
>  ...
>endcase
>
>
>If "x" happens to be equal to 500, Visual FoxPro must analize all 500 cases, before carrying out the desired action. If this happens often, i.e., in a tight loop, performance will be bad. It might be much more efficient to split it, for example, as follows:
>
>
>do case
>case x <= 100
>  do case
>  case x <= 10
>    case x = 1
>      ...
>    case x = 2
>      ...
>  case x <= 20
>    case x = 11
>      ...
>    case x = 12
>      ...
>case x <= 200
>...
>
>
>Or something similar. Much less CASEs to be analyzed, for any given number.

Good idea Hilmar. I was taught to place the CASE statements most likely to occur first. That is sometimes easy and worthwhile and at othertimes... :)
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