On May 27 2007 16:37, Stefan Richter wrote:
>Jan Engelhardt wrote:
>> + if (is_prime(number) == true)
>> + return 0;
>> + if (is_prime(number) == false)
>> + return 1;
>> +
>> +should be:
>> +
>> + if (is_prime(number))
>> + return 0;
>> + if (!is_prime(number))
>> + return 1;
>> +
>> +As far as pointers or functions returning an integer are concerned,
>> +using long form tests helps to distinguish between pointers and bools
>> +or functions returning boolean or integer, respectively.
>> +Examples are:
>> +
>> + if (p == NULL)
>> + return 1;
>> + if (!p)
>> + return 0;
>> +
>> + if (strcmp(haystack, needle) == 0)
>> + return 1;
>> + if (!strcmp(haystack, needle))
>> + return 0;
>
>The latter two examples seem odd. Didn't you mean the following?
See how much confusion it all makes!
Right, it was intended -- first the long form is shown and then the
shorter one (and "long form tests help to distinguish"):
if (p == NULL) /* this way please */
return 1;
if (!p) /* Everytime you shorten it, God kills a kitten */
return 0;
/* so perhaps don't do it if you love animals or
know someone who does. */
I seem to have forgotten more comments/explanation.
> if (p == NULL)
> return 1;
> if (p)
> return 0;
>
> if (strcmp(haystack, needle) == 0)
> return 1;
> if (strcmp(haystack, needle))
> return 0;
>
>Perhaps better:
>
> if (p == NULL)
> return NO_MEMORY;
> if (p)
> return MEMORY;
>
> if (strcmp(haystack, needle) == 0)
> return IS_SAME;
> if (strcmp(haystack, needle))
> return IS_DIFFERENT;
>
>However, to follow your argument about non-boolean expressions, the
>following would be more consequently going into your direction:
>
>I.e., why do the explicit comparison with 0 or NULL only when it is
>tested for equality, but not when testing for inequality?
>
>However, I agree with Scott Preece that these rules should be left out
>of CodingStyle because they are contentious.
>
>(Disclosure: I am personally used to "if (p)" and "if (!p)" tests of
>pointers and many integer expressions, but I tend to the longer form in
>less obvious cases like "if (strcmp(a, b) != 0)".)
Jan
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