Sep 17, 2008

# Math.abs has an edge case...

Consider the following Java code:

- int ai = Math.abs( i );
- assert ai >= 0;

Will the assert ever fire?

Yes, it turns out that it can fire if `i = Integer.MIN_VALUE`

, and you have been warned about this in the Math.abs javadoc, which states “*Note that if the argument is equal to the value of Integer.MIN_VALUE, the most negative representable int value, the result is that same value, which is negative.*’

Keep this in mind when looking at such innocent looking code...