how do i test a number negative or positive?

[dswimboy]

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[Kanji]

For your original question, comparing with the abs value should do the trick ...

if ( $num == abs($num) ) {
    print "positive";
} else {
    print "negative";
}

... but for your revised question, you should check the modulus ...

if ( $num % 2 ) {
    print "odd";
} else {
    print "even";
}

However, if all you really want to do is alternate colours...

Edit by dws per author's request

[PodMaster]

check out perlsyn and perlop (in particular the comparison operators)

my $num = $_ = 4;
if($num >= 0) {
   die "$num is positive";
} else {
   die "$num is negative (but we already knew that)";
}

# or even ;)
my $num = $_ = -4;
if(substr($num,0,1,) eq '-') {
   die "I, $num, feel so negative today";
} else {
   die "$num says 'Things are looking up'";
}

[dswimboy]

wow...i'm sorry. how do you test if a number is even or odd...i'm sorry

Originally posted as a Categorized Answer.