replace
int str_rev(char* s)
{
char* s_end;
char tmp;
if (!s) return -1;
s_end = s + strlen(s) - 1;
for (; s < s_end; s++, s_end--)
{
tmp = *s;
*s = *s_end;
*s_end = tmp;
}
return 0;
}
with something like this...
int str_rev(char*s)
{
int length = strlen(s);
int pos = 0;
while(length > 0)
{
s[length--] = s[pos++];
}
}
Untested but I would think it should be a little bit faster.
On Thu, May 2, 2013 at 8:25 AM, Sasha Pachev <[email protected]> wrote:
> OK, the gauntlet has been thrown.
>
> http://asksasha.com/strrev.c
>
> coded in 25 minutes. When compiled with -O3 gives me this on my laptop:
>
> bash-4.1$ time ./strrev /usr/share/dict/words > /dev/null
>
> real 0m0.055s
> user 0m0.053s
> sys 0m0.002s
>
> my /usr/share/dict/words can be downloaded from here:
>
> http://asksasha.com/words
>
> when compiled with default flags (with gcc 4.4.5) I got 0.09 s of real time
>
> Levi, beat this in Haskell. Barry, Dale, beat this in Java. Anybody
> else, beat this in your language of choice including C - I do not
> claim that my implementation is the best. Post your development time.
> If you think the rules are not fair, feel free to protest.
>
> For those who cannot read C, the program reads the strings from the
> file given by the first argument delimited by \n, reverses each and
> prints the result to stdout.
>
> To compile it:
>
> gcc -O3 -o strrev strrev.c
>
> Yes, and for those who are too smart for their own good - your program
> must dump out the correct result when you print to stdout instead of
> redirecting to /dev/null, and it must work correctly on any file that
> has lines shorter than 512 bytes. If the line is longer than that it
> can truncate the string, but must not crash.
>
>
> --
> Sasha Pachev
>
> Fast Running Blog.
> http://fastrunningblog.com
> Run. Blog. Improve. Repeat.
>
> /*
> PLUG: http://plug.org, #utah on irc.freenode.net
> Unsubscribe: http://plug.org/mailman/options/plug
> Don't fear the penguin.
> */
>
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