problem with number formatting code.

Posted by Typhon on Sun 05 Oct 2008 04:23 PM — 5 posts, 23,142 views.

Typhon USA Sun 05 Oct 2008 04:23 PM #0

seems like i'm missing something real small here but nonetheless i cant find it.
added :


char *short_num(int num)
{
	static char buf[12];
	buf[0] = '\0';
	
	if (num <= 9999)
	{
		sprintf(buf, "%d", num);
		return buf;
	}
	sprintf(buf, "%5.1f%c", (float)num / 1000, num>1000000 ? 'm' : 'k' );
	return buf;
}

when calling that function in

ch_printf(ch, "%-4s/%-4s ", short_num(ch->hit), short_num(ch->max_hit) );

it returns the exact same figure for both :(
11.4k/11.4k when ch has 30,000 max_hit.
thanks
-typ

Zeno USA Sun 05 Oct 2008 05:33 PM #1

This may be related, but in Smaug if you use num_punct (which does the same thing) on the same line, it won't work.

Typhon USA Sun 05 Oct 2008 06:06 PM #2

haha breaking up the code works. thanks :)

Nick Cash USA Mon 06 Oct 2008 05:58 AM #3

static char buf[12];

Although you figured it out, I'd like to point out it is the use of a static variable that causes this. It avoids memory allocation management, but at the expense of situations like this. As you have discovered, it works if you break up the code calling the functions.

If I had to guess, the value retained in the buffer is from the last call completed since the return value each time points to the same static character array. Because you put two calls in one line, the second call was stacked on the first call, thus executing the second call first, causing it's value in 'buf' to be wiped out by the next call.

Nick Gammon Australia Forum Administrator Mon 06 Oct 2008 07:22 AM #4

You would be 100% correct about that.