i have some other related problem. this is to convert ascii character 'A' to sjis (japanese full-width alphanumeric character) 'Ａ' .

The easiest way might be to convert "plain ascii" characters into the unicode "fullwidth" characters first, then "Encode::encode()" the unicode string into shiftjis for output.

The unicode range for the "fullwidth" ASCII characters begins at \x{FF01} for "!" (exclamation mark), and then proceeds through the normal ASCII character sequence up through \x{FF5E}. So one way to convert "plain ASCII" to "fullwidth ASCII" would be like this:

use Encode;

# pick one of the following lines to uncomment
# (depends on what sort of display terminal you use):
#binmode STDOUT, ":utf8";
#binmode STDOUT, ":encoding(shiftjis)";

$_ = join( '', map { chr() } 0x21 .. 0x7e ) . "\n";  # this is a test 
+string
print;

s/([!-~])/chr(ord($1)+0xFEE0)/eg;  # convert plain ASCII to CJK fullwi
+dth ASCII

# print;  # uncomment this when you have chosen which binmode line to 
+use
[download]

(update: adding missing colon in 2nd binmode line)