> A loop can always be expressed with tail recursion.

If I were writing the code in assembly, I would just use a loop, because that's what the machine is optimized to perform.

> But this is also a symptom of standard c's problem of not allowing one to define functions inside of functions.

There are extensions that do this; however, they cannot create a scoped closure for you so nobody cares to use them for anything.

> and these have to be coalesced into a single flag for the loop.

Or just use 'goto'.