use strict;
use warnings;

print "A-B =~ /A.+B/ --> ";
print "worked" if "A-B" =~ /A.+B/;
print "\n";

print "A-B =~ /A.*B/ --> ";
print "worked" if "A-B" =~ /A.*B/;
print "\n";

print "AB =~ /A.+B/ --> ";
print "worked" if "AB" =~ /A.+B/;
print "\n";

print "AB =~ /A.*B/ --> ";
print "worked" if "AB" =~ /A.*B/;
print "\n";

##</code><code>##

A-B =~ /A.+B/ --> worked
A-B =~ /A.*B/ --> worked
AB =~ /A.+B/ -->
AB =~ /A.*B/ --> worked