Circular Queue: Array Implementation and Condition Checks

Circular Queue linear queue ke false overflow drawback ko overcome karta hai. Isme array ke last element (index N - 1) ko conceptually first element (index 0) ke saath connect kiya jata hai using Modulo Arithmetic (% N).

                 [0]
              /       \
          [4]           [1]
             \         /
             [3] --- [2]

Wrap-Around Formula:
Next Position = (current_position + 1) % Capacity

Condition Checks in Circular Queue

• Empty Condition: FRONT == -1
• Full Condition (Overflow): (REAR + 1) % CAPACITY == FRONT

Enqueue and Dequeue Operations

ENQUEUE_CIRCULAR(Q, CAPACITY, val)
1. If (REAR + 1) % CAPACITY == FRONT then:
       Print "Circular Queue Overflow!"; Return
2. If FRONT == -1 then: Set FRONT = REAR = 0
3. Else:
       Set REAR = (REAR + 1) % CAPACITY
4. Set Q[REAR] = val

DEQUEUE_CIRCULAR(Q, CAPACITY)
1. If FRONT == -1 then:
       Print "Circular Queue Underflow!"; Return -1
2. val = Q[FRONT]
3. If FRONT == REAR then:
       Set FRONT = REAR = -1    [Only 1 element was present]
4. Else:
       Set FRONT = (FRONT + 1) % CAPACITY
5. Return val

Agli post me hum cover karenge Queue Implementation using Linked List.