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SubjectRe: [PATCH] [condingstyle] Add chapter on tests
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?

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:

if (p == NULL)
return NO_MEMORY;
if (p != NULL)
return MEMORY;
if (strcmp(haystack, needle) == 0)
return IS_SAME;
if (strcmp(haystack, needle) != 0)
return IS_DIFFERENT;
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)".)
--
Stefan Richter
-=====-=-=== -=-= ==-==
http://arcgraph.de/sr/
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