Create a data structure that represents a circular buffer of a fixed size. A circular buffer overwrites existing elements when the buffer is being filled beyond its fixed size. The class you must write should:
- Prohibit default construction
- Support the creation of objects with a specified size
- Allow checking of the buffer capacity and status (empty(), full(), size(), capacity())
- Add a new element, an operation that could potentially overwrite the oldest element in the buffer
- Remove the oldest element from the buffer
- Support iteration through its elements
