[Myrmornis]

Just to be clear, the rules of your swap challenge are that the arguments of the function have to be ints, not allowed to be int *, right?

Also you say "two objects", but if the objects were compound, e.g. arrays, then I could write swap in C.

[lvh]

Yes. It's about swapping the arguments. With a struct or an array or a pointer or whatever, you're not swapping the arguments themselves; but the fact that there are so many things that do something slightly similar probably illustrates the limited utility of pass-by-reference.