Perl - Printing the next line - regex

Question

I am a noob Perl user trying to get my work done ASAP so I can go home on time today :)
Basically I need to print the next line of blank lines in a text file.
The following is what I have so far. It can locate blank lines perfectly fine. Now I just have to print the next line.
open (FOUT, '>>result.txt');
die "File is not available" unless (#ARGV ==1);
open (FIN, $ARGV[0]) or die "Cannot open $ARGV[0]: $!\n";
#rawData=<FIN>;
$count = 0;
foreach $LineVar (#rawData)
{
if($_ = ~/^\s*$/)
{
print "blank line \n";
#I need something HERE!!
}
print "$count \n";
$count++;
}
close (FOUT);
close (FIN);
Thanks a bunch :)

Answer 1

open (FOUT, '>>result.txt');
die "File is not available" unless (#ARGV ==1);
open (FIN, $ARGV[0]) or die "Cannot open $ARGV[0]: $!\n";
$count = 0;
while(<FIN>)
{
if($_ = ~/^\s*$/)
{
print "blank line \n";
count++;
<FIN>;
print $_;
}
print "$count \n";
$count++;
}
close (FOUT);
close (FIN);
not reading the entire file into #rawData saves memory, especially in the case of large files...
<FIN> as a command reads the next line into $_
print ; by itself is a synonym for print $_; (although I went for the more explicit variant this time...

Answer 2

Elaborating on Ron Savage's solution:
foreach $LineVar (#rawData)
{
if ( $lastLineWasBlank )
{
print $LineVar;
$lastLineWasBlank = 0;
}
if($LineVar =~ /^\s*$/)
{
print "blank line \n";
#I need something HERE!!
$lastLineWasBlank = 1;
}
print "$count \n";
$count++;
}

Answer 3

I'd go like this but there's probably other ways to do it:
for ( my $i = 0 ; $i < #rawData ; $i++ ){
if ( $rawData[$i] =~ /^\s*$/ ){
print $rawData[$i + 1] ; ## plus check this is not null
}
}
J.

Answer 4

sh> perl -ne 'if ($b) { print }; if ($b = !/\S/) { ++$c }; END { print $c,"\n" }'
Add input filename(s) to your liking.

Answer 5

Add a variable like $lastLineWasBlank, and set it at the end of each loop.
if ( $lastLineWasBlank )
{
print "blank line\n" . $LineVar;
}
something like that. :-)