What is better, math or logic?

**thetinman** · 02-24-2006

Take the following code snippets that find the absolute value of the variable x.

This one uses logic:

Code:

if ( x < 0 )
x *= -1.0f;

And this one which uses math:

Code:

x = fabsf( x );

Given that the probability of x being negative is equal to the probability of x being positive, which of the two methods is best?

**Salem** · 02-24-2006

Neither.

**OnionKnight** · 02-24-2006

Don't know much about how floating-point works indepth but I think that

Code:

if ( x < 0 )
    x = -x;

would be faster for the first method.

**dwks** · 02-25-2006

The compiler would probably optimise both to be the same thing (assuming you meant fabs(), not fabsf()).

Thread: What is better, math or logic?