use strict;
use warnings;

while (my $line = <DATA>) {
    if ($line =~ /#include [<"](\S+\.h)[>"]/) {
        print "$1\n";    #not printing the header third case
    }
}

__DATA__
#include "string.h"
#include <stdlib.h>
#include <sys/dispatch.h>

##</code><code>##

string.h
stdlib.h
sys/dispatch.h