use strict;

my $word = 'abcdefabcdeab';
my ( %counters, $total );
while ( $word =~ /([a-c])/gi )
{
    $counters{$1}++;
}

foreach my $letter ( sort keys %counters )
{
    print "\n$letter: " . $counters{$letter};
    $total += $counters{$letter};
}
print "\nTotal: $total";