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Hello,
Frankly speaking fall-through is one of BEST features of switch() statement.
I use it thousands of times. Implementations lacking that are missing
single most important thing in switch() statement.
K&R "The C Programming Language" book is really recommended reading.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "Nigel Rowe" <rho@xxxxxxxxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Friday, May 25, 2007 12:12 PM
Subject: Re: [amibroker] Re: Nested Switch() statements
> On Fri, 25 May 2007, Ton Sieverding wrote:
>> Can you please explain me why 'switch statements are a frequent
>> source of bugs' ? If the last CASE is a DEFAULT then all possible
>> cases are covered. Or am I missing something in the AFL SWITCH
>> statement ?
>>
>> switch ( expression )
>> {
>> case constant-expression1 : statement;
>> case constant-expression2 : statement;
>> ...
>> case constant-expressionN : statement;
>>
>> default : statement;
>>
>> }
>>
>>
>> Ton.
>
> The 'standard' error when using a switch statement in 'C' and presumably
> AFL, is forgetting to put 'break;' statements in.
>
> To paraphrase your example (above) so it looks like this:-
>
> switch ( expression )
> {
> case constant-expression1 : statement1;
> case constant-expression2 : statement2;
> ...
> case constant-expressionN : statementN;
> default : statement_default;
> }
>
> If you leave out the break statements, and
> expression==constant_expression1 you will execute statement1 (what you
> wanted) AND ALSO statement2 AND ALSO statement3 AND ALSO ... statementN
> AND ALSO statement_default.
>
> It's sometimes called the 'fall-through' bug. It's easy to miss, can be
> a right pain!
>
>
> --
> Nigel Rowe
> rho \N{COMMERCIAL AT} swiftdsl \N{FULL STOP} com \N{FULL STOP} au
>
>
>
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Please note that this group is for discussion between users only.
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