sub IsItem {
# usage: IsItem(item to find, pointer to list to search)
  my $ref = @_[1];
  foreach my $e (@{$ref}) {
    if (@_[0] eq $e) {return 1}
  }
  return 0;
}

my @a = (10,20,30);
print 'IsItem=',IsItem(20,\@a);
print 'IsItem=',IsItem(5,\@a);