Ok, this is pretty
simple to do, but I've found that many people think it can't be done...so here it is, in all of it's
perlified glory. This takes two arguments on the
command line, stores them in 2 seperate variables, then swaps them, without using a third. The print statements are not neccessary, they are only there to
prove that this does indeed work.
This is applicable to most any
programming language you can think of.
#!/usr/bin/perl
$a=$ARGV[0]
$b=$ARGV[1]
print "$a\n";
print "$b\n";
$a=$a+$b;
$b=$a-$b;
$a=$a-$b;
print "$a\n";
print "$b\n";
No preformatting tool was used on the above text - all mistakes, syntactical, logical, or otherwise, are
mine. I also haven't tested this for x as x->+/- infinity yet, so if it doesn't work for some obscure value, tough beans. I thought it was
nifty.