http://qs321.pair.com?node_id=11124043

in reply to Pointers and References

A couple lines fixed...

```#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11124042
use warnings;
use v5.10;

my \$variable = 22;
my \$pointer = \\$variable;

say "The address of \\$varible, which contains the value \$variable,";
say "is \$pointer";

\$\$pointer = 25;

say "Look at that!  \\$variable now equals \$variable";

sub sum_and_diff {
my \$a = shift @_;
my \$b = shift @_;
#    my \$res = \(shift @_); # why does the "\" work here? # it didn't
my \$res = shift @_;
my \$sum = \$a + \$b;
\$\$res = \$a - \$b;
return \$sum;
}

my \$b = 2;
my \$diff;  # this is line 27
my \$pointer_to_diff = \\$diff;

say "the sum of 5 and \$b is ", &sum_and_diff(5, \$b, \$pointer_to_diff);
#say "and the difference is ", \$pointer_to_diff;
say "and the difference is ", \$\$pointer_to_diff;

say "the sum of 9 and \$b is ", &sum_and_diff(9, \$b, \\$diff);
say "and the difference is ", \$diff;  # this is line 34

Outputs:

```The address of \$varible, which contains the value 22,
is SCALAR(0x55d283691438)
Look at that!  \$variable now equals 25
the sum of 5 and 2 is 7
and the difference is 3
the sum of 9 and 2 is 11
and the difference is 7