How can I swap two Perl variables without using the third?

Question

I want to swap two variables values without using the third variable in Perl, e. g.:

my $first = 10;
my $second = 20;

Please suggest me how

Answer 1

You can do this relatively easy using simple maths.

We know;

First = 10
Second = 20

If we say First = First + Second

We now have the following;

First = 30
Second = 20

Now you can say Second = First - Second (Second = 30 - 20)

We now have;

First = 30
Second = 10

Now minus Second from First, and you get First = 20, and Second = 10.