while (<IN>)
{

##</code><code>##

   if (/^Curve(\d):/.../^\s*$/)
   {

##</code><code>##

     if (defined($1) && $1==1 && /^\d/) {print $c1 "$_\n";};
     if (defined($1) && $1==2 && /^\d/) {print $c2 "$_\n"};

##</code><code>##

#!/usr/bin/perl
use warnings;
use strict;


my %out = map {
    my $name = "curve$_.out";
    open my $FH, '>', $name or die "cannot open $name $!";
    $_ => $FH;
    } 1, 2;

my $in ='curve12.data';
open my $IN, '<', $in or die "cannot open $in $!";

while ( <$IN> ) {
    if ( /^Curve(\d):/ .. /^\s*$/ ) {
        next unless /^\d/;
        exists $out{ $1 } and print { $out{ $1 } } "$_\n";
    }
}