my @ints = ( int( rand() * 100 ), int( rand() * 100 ) );

print "Which is larger?\n1) $ints[0]\n2)$ints[1]?\n";

chomp( my $input = <STDIN> );
print "$ints[ $input ] is larger.\n";
[download]

I read this, did a double take, then laughed out loud. :-)

To do the latter without a comparison operator, check equality to "0", or test if it starts with a "-" character, for example with a regexp, or with substr.

You can compare two integers for equality by exploiting the properties of "exclusive or" (^). See perlop.

print $a.(qw(< == >))[1+eval{($a-$b)/abs($a-$b)}].$b,$/;
[download]

print+('equal','a is smaller','b is smaller')[length($a-$b)-length($b-$a)];

or

print 1x($a-$b)?'b is smaller':1x($b-$a)?'a is smaller':'equal';

$a = 3;
$b = 4;

print (sqrt(($a-$b)**2) - ($a-$b));
[download]

What's wrong with abs?

print abs($a-$b) - ($a-$b);
[download]

abs($a-$b) - ($a-$b) equals 0 when $a>=$b, and equals 2*abs($a-$b) when $a<$b.

Perhaps you meant to say abs($a-$b)/($a-$b). This would produce the same (-1,0,1) that <=> returns, but it needs special handling to avoid division by zero, e.g. the eval in tye's post.

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.

Explain what it is you're trying to do.

If I had to guess, I'd say "Get someone else to do my homework."

But, then, maybe I'm too cynical.

How to compare two signed integers without using the comparision operators in perl.

"Uhh ... that'll take me three weeks, broken down as follows: 1 day for coding, the rest for meetings to explain why I only need 1 day for coding."

You can use string comparison on positive, unsigned integers, or even unsigned floating point numbers, if you make sure the number of digits left of the decimal point (if any) are the same for all numbers. Thus, after using sprintf with a proper template.

This doesn't work if at least one of the numbers is negative.

I don't think it matters for this particular case, as string comparison is comparison nevertheless, but still... It's the only reason I can think of why the sign would matter.

p.s. It's even an excellent way to compare groups of strings/numbers in one comparison, for example, for sort.

print $a, ' is ', ('smaller', 'equal', 'greater')[1+($a<=>$b)], ' than
+ ', $b;
[download]

FWIW, the in the OP's clarification of this question, the list of excluded operators was  ==,<,>. The way I read the clarification and the original question, I believe that <=> was not excluded, and could well have been what the OP was looking for, rather than the mathematical monstrocitoes offered.

C'est la vie.

---

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller

artist

It is not a practical problem, it is just a quiz to rewrite the following code:

($a == $b) ? print "equal" : ( ($a <  $b) ? print "a is small" : print
+ "b is small");
[download]

without using the comparision operators like ==,<,> .