Re: efficiency concern: when to really use unsigned ints and when not to

From: CBFalconer (cbfalconer_at_yahoo.com)
Date: 02/16/04 

Date: Mon, 16 Feb 2004 20:12:59 GMT

anony*mouse wrote:
>
... snip ...
>
> As an exercise consider the additional checks that need to be
> taken in the check() function below. How many would be removed
> by making a and b unsigned?
>
> int check(signed int a, signed int b)
> {
> /* a and b are considered untrusted numbers. */
>
          if ((a < 0) || (b < 0)) return 0;
> if (a + b < 50)
> return 1;
> else
> return 0;
> }

The above suffices for any system which has integer overflow
detection. Now consider the ugly tests required if a and b are
unsigned, so that overflow of a + b cannot occur. 

-- 
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
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