add a "suffix" to a variable in a array

[Laura]

I dont know if I can explain this correctly by here goes.
I am trying to write a perl program that takes a file let say it looks
like this...
xxxx001,00 0 05 21,TELN NOT
xxxx002,00 0 01 30,TELN NOT
xxxx008,00 0 04 15,TELN NOT
xxxx013,00 0 02 30,CUST HAS
xxxx015,00 0 10 22,CUST HAS

I want to also insert a few things to this file...
I want to prompt user to enter in
print "Enter BLD:"; $bld=<STDIN> ; chomp $bld;
print "Enter ROOM:"; $ROOM=<STDIN> ; chomp $ROOM;

Also I want a areacode fixed to the first column so when all is said
and done, I have part of the script but can not add the areacode to
it???

#!/opt/perl/bin/perl
$acode="204";
print "Enter BLD:"; $bld=<STDIN> ; chomp $bld;
print "Enter ROOM:"; $room=<STDIN> ; chomp $room;
while(<ARGV>) {
chomp;
@a=split(",",$_);
print join(",",$a[0],$bld,$room,$a[1],$a[2],$a[3],"\n") ;

How do I add 204 at the beginning of the [1]?

204xxxx001,EAST_BLD,ROOM1,00 0 05 21,TELN NOT