use strict;
use warnings;
use utf8;
binmode STDIN, ':encoding(cp932)';
binmode STDOUT, ':encoding(cp932)';
binmode STDERR, ':encoding(cp932)';

my %address = (
"鈴木" => "東京都千代田区",
"山田" => "東京都葛飾区",
"本田" => "愛知県名古屋市",
"遠藤" => "大阪府堺市"
);

my @keylist = keys(%address);
my $keycount = keys(%address);

print "要素数は $keycount です。\n";

for (my $i = 0; $i < $keycount; $i++){
  print "$keylist[$i]\n";
}