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NNTP-Posting-Date: Sat, 24 Sep 2011 06:48:56 -0500
Message-ID: <4E7DC3AA.427D@mindspring.com>
Date: Sat, 24 Sep 2011 07:48:58 -0400
From: pete <pfiland@mindspring.com>
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Subject: Re: To use Perl like conditional assignment in C
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.c:10848

Ya Shou wrote:
> 
> Hello,
> 
> I want to assign an uncertain value to a variable, this variable with
> values in the configuration file, reads the configuration file
> through a function to return to the read configuration value, if not
> configured or the value of non-compliance, will return 0 for failure,
> when this, I will to give it a default value assigned.
> 
> However, I found it seem impossible to achieve this in C, but much
> easier to implement in Perl, see below:
> 
> cfgval = loadConfig () || DEFAULT_VAL;
> 
> In C '||' operator does not return the value of the expression which
> is true, but returns 1 or 0, so that I can not be used in a similar
> way. I considered a program in C is:
> 
> cfgval = loadConfig ()? loadConfig (): DEFAULT_VAL;
> 
> And however, this approach to involve a duplication of code, it is
> ugly, the other will call loadConfig function twice, inefficient and
> likely to cause unnecessary accidents.
> 
> Of course, if / else statement can achieve this functionality, but
> this method requires an additional variable, and not look simple. As
> follows:
> 
> int loadval = loadConfig ();
> if (loadval! = 0) {
>    cfgval = loadval;
> } else {
>    cfgval = DEFAULT_VAL;
> }
> 
> Or
> 
> int loadval;
> cfgval = (loadval! = 0)? loadval: DEFAULT_VAL;
> 
> I would like to ask you is, in this case, there is nothing more
> beautiful realization?

    cfgval = loadConfig ();
    if (cfgval == 0) {
        cfgval = DEFAULT_VAL;
    }

-- 
pete