sub one{
    &two shift, shift;
}

##</code><code>##

use strict;
use warnings;
one(1,2,3,4);
sub two {
    print "Elements : \n @_ \n";
}
sub one {
    two shift, shift;
}

##</code><code>##

use strict;
use warnings;
sub two;      # forward declaration
one(1,2,3,4);
sub one {
    two shift, shift;
}
sub two {
    print "Elements : \n @_ \n";
}