so why not do it *the right way* and just use bitwise xor?

a = a xor b
b = a xor b
a = a xor b

correct(the contract should specify that the references passed in may not be equal), works for all data types, and saves one precious variable.

I suppose if someone is at the level of using templates, the concept of exception safety should be introduced somewhere close.

For someone who’s new, I’d let them start with Ruby, Javascript, Logo, Object Pascal, or even Java. C++ sounds like a poor choice for an introductory language.

@Michael,
If you are creating an application in C++ and you want to swap two variables, you most definitely would use std::swap function. If you read carefully, I was talking about people who are starting to learn programming, and hence need to write their own swap, search, sort etc. functions. The exercise clears up points like the ones discussed in this post.
I didn’t even bother to make the swap function inline; my example focussed only on the right way to do the swapping. But I will post the std::swap functions as implemented by major STL implementors to show how simple they actually are.

The only correct way of swapping is don’t bother writing your own swap. Use std::swap directly if you can, call it if you cannot.

std::swap(a, b).

Done. Never reinvent your own wheel.

Your 1st way is wrong because it doesn’t have a “nothrow” guarantee. It’s especially important when memory is tight.

I certainly hope you aren’t doing this with polymorphic objects. Please do not do bitwise operations on polymorphic objects. If you don’t know why please do not ever write code again. Also whoever wrote that second version, stop coding as well. You are asinine and dangerous.