#!/usr/bin/perl

use strict;
use warnings;

my $secret = 1 + int rand 100;

while (print "Your guess > ") {
    local $_ = <>;
    chomp;

    if (!/\S/ || /quit/i || /exit/i) {
        print "Too bad, you gave up.\n";
        exit;
    }

    if (/\D/) {
        print "You didn't enter a non-negative integer\n";
        next;
    }

    if ($_ == $secret) {
        print "You guessed the number correctly.\n";
        exit;
    }

    my $answer = $_ < $secret ? "less" : "greater";

    print "The number you entered is $answer than the secret number\n";
}

__END__