Of course that code is broken (relies on undefined behavior) when i is zero, which is a totally reasonable input for a rotate function. A nice illustration of t

Of course that code is broken (relies on undefined behavior) when i is zero, which is a totally reasonable input for a rotate function. A nice illustration of the pitfalls of undefined behavior. You can find a correct implementation in a blog post by John Regehr [1]. [1] https://blog.regehr.org/archives/1063 https://blog.regehr.org/archives/1063