You're missing the point: it's not that using an array is slower, it's that "int n[3]" can mean something completely different than "int a,b,c" does. A lot of comments on this thread have suggested that the two are interchangeable: they aren't.

Using an array here is wrong: it needlessly complicates the code (now in addition to everything else, I have to remember how big the array is and what each (unnamed) index corresponds to), possibly makes the compiler emit worthless loads/stores, and let's me potentially blow up the world if I mess up and access out-of-bounds.