Thank you very much for your help!

Your code works fine with the variable.. but when i try to read a file, the number of the lines are wrong!

For example if i put the content of your variable $sluperdfile and add only one line such as //Hello:

#Content of the file test.txt
Blah blah blah
//Hello
blah blah Blah // single line c++ comment
more blahs "quoted string with /* " blah
blah blah blah /* single line c comment */ blah
blah blah /*
    multi line
    c style comment */
some more blahs
// another single line c++ comment
blah blah blah
[download]

And now the source code:

use strict;

undef $/;#In order to read the whole file at once
open(F,"test.txt");

my @matches =  <F> =~
m{
     ( /\* .*? \*/) | ( \/\/[^\n]*)
     | " (?: [^"\\]* | \\. )* "
     | ' (?: [^'\\]* | \\. )* '
     | . [^/"']*
   }xgs;
@matches = grep {defined $_} @matches; #get rid of undefs
my $linenum = 1;

foreach my $match (@matches) {

        $slurpedfile =~ /\Q$match/;
        my $before = $`;
        $slurpedfile = $';
        my $matched = $&;
        $linenum += $before =~ tr/\n/\n/;
        print "Line $linenum\t$match\n";
        $linenum += $match =~ tr/\n/\n/;
}
[download]

How can i grab the line numbers correctly! What variable should i put instead of $slurpedfile? According that i want to read directly from a file?

And another issue.. Is it possible to the output be something like this:

Line 12        //Hello
Line 23        // single line c++ comment
Line 34        /* single line c comment */
Line 45        /*
Line 46          multi line
Line 47                  c style comment */
Line 58        // another single line c++ comment
[download]

Instead of:

Line 12        //Hello
Line 23        // single line c++ comment
Line 34        /* single line c comment */
Line 45        /*
    multi line
    c style comment */
Line 58        // another single line c++ comment
[download]

Thank you.. for your help...