This would better be coded using a hash:

use strict;
use warnings;

my %prims =( 
 "int"    => 1,
 "char"   => 1,
 "long"   => 1,
 "double" => 1,
 "static" => 1
);

while(<>) {
  if($prims{$_}) {
    print "Found item $_\n";
  }
}
[download]

Update:
If you absolutely need to have the @prim array, then create the hash on-the-fly using map:

...

my @prim = (("int","char","long","double","static");
my %prim = map { $_ => 1 } @prim;

...
[download]

Update2

After reading moritz's take on this, his seems to be what you're looking for.

I was somehow thinking that you were parsing chunks (ie. words) and then seeing if that word existed in your array/hash.

moritz is also spot-on mentioning that you're not handling the newlines at the ends of lines.