FIFOs, First-In-First-Out
enqueue(x)dequeueis_empty()
If try to dequeue from an empty queue, will get EmptyQueueException.
Whenever enqueue (resp. dequeue) we increment rear (resp. front).
pos = (pos + 1) % 6
To generalise:
pos = (pos + 1) % size
var queue = new int[MAXQUEUE];
int front = 0;
int size = 0;-
font + size <= MAXQUEUE
pos∈ [font, font + size)
-
font + size > MAXQUEUE
pos∈ [font, MAXQUEUE) ∪ [0, front + size - MAXQUEUE)
-
font∈ [0, MAXQUEUE) -
size∈ [0, MAXQUEUE]
rear = (front + size) % MAXQUEUE
if size == MAXQUEUE, the queue is full.
- Is not full?
- Insert data into index
(front + size) % MAXQUEUE - Add 1 to
size
- Is not empty?
- Get value at index
front front = (front + 1) % MAXQUEUE- Minus 1 to
size