Programming Perl, 4th Edition

abs

abs VALUE
abs

This function returns the absolute value of its argument.

$diff = abs($first – $second);

Here and in the examples following, good style (and the strict pragma) would dictate that you add a my modifier to declare a new lexically scoped variable, like this:

my $diff = abs($first – $second);

However, we’ve omitted my from most of our examples for clarity. Just assume that any such variable was declared earlier.