/*
> > int ptr[] <=> int *ptr
>
> Oo, oo! This brings to mind a useful language extension:
>
> a <=> b;
>
> for exchanging the contents of a and b. How often have you written:
>
> { register type t;
>
> t = a;
> a = b;
> b = t;
> }
Rarely. I use: `a ^= b; b ^= a; a ^= b;' Only worx for integer types.
*/