#!/usr/bin/perl -w
use strict;
my @list = qw(Charles Cody Gina);

# pass the array to the sub to avoid value reuse.
&action(@list);

sub action {
  my @list = @_;
  for my $i(@list) {
    # tests the return value of decide and only prints
    # if it is true (1)
    print "$i\n" if decide($i);
  }
}

sub decide {
  my $i = shift;
  # returns 1 if it is a match otherwise nothing
  # is returned.
  return 1 if $i =~ m/^C/;
  # you could add an explicit return 0 if you want
  # return 0;
}