A circular buffer is a fixed-size data structure that contains two indices, a head index and a tail index that connects to the beginning of the buffer. When the buffer is full, the head index will loop back to 0. Their main purpose is to accept incoming data until their capacity is full, and then overwrite older elements.
Circular buffers are useful when you need a FIFO data structure. They are similar to the queue data structure, except the tail index wraps to the front of the buffer to form a circular data structure.
Since circular buffers are a fixed size, as they become full the older elements will be overwritten. Because of their fixed size, it is more efficient to use an array data structure internally to store the data instead of a linked list. Generally, once you create a circular buffer, the size will not increase, so the buffer memory size should stay pretty static. An implementation could include the capability to resize the buffer and move the existing elements...
