use strict;
use warnings;
my $str = qq/
1 2 3 4
----------
C 2, 2(13) R 2, 2( 8) C 2, 2(13) 
----------
C 2, 2(11) C 2, 2(13) R 2, 2(18) 
----------
C 2, 2(18) C 1, 2(11) C 2, 2(13) 
----------
C 1, 2(11) C 2, 2(18) C 2, 2(11) 
/;

my @match = ($str =~ /([A-Z]\s\d+,\s\d+\(\s*\d+\))/g);
print "$_\n" for @match;

__END__

C 2, 2(13)
R 2, 2( 8)
C 2, 2(13)
C 2, 2(11)
C 2, 2(13)
R 2, 2(18)
C 2, 2(18)
C 1, 2(11)
C 2, 2(13)
C 1, 2(11)
C 2, 2(18)
C 2, 2(11)
[download]

my $str = slurp('file.txt');

sub slurp {
        open(F, shift);
        local $/ = undef;    # undef record seperator
        my $txt = <F>;
        close(F);
        return $txt;
}
[download]

I am wanting to read the strings of interest from a file e.g.


$in_filename = "test.out"; 
open (IN,"$in_filename") or die "Can't open $in_filename:$!\n";
[download]

They are not already stored in an array so I cannot use
@array = qw (stuff);
as you have displayed in the start of your solution.
but yes, the output that you've shown is exactly what I want.
cheers

It was $str = qq/ stuff /; a string in double quote.