Summary

A circular_array treats a fixed-size array as a loop. Indices use modulo_indexing to wrap_around at the ends. Track head, tail, and capacity. Moving to the next slot is constant_time. Common uses include ring_buffer, circular_queue, and round_robin scheduling. Key idea: compute index as (i + step) % n. Normalize negatives with index_normalization like (i + n) % n. Remember full vs empty rules in buffers. A circular array saves shifts and simplifies rotating data.