1.7.1 Circule Queue

• circular array representation of a queue
  
  1. Initial condition : front = rear = 0
  2. Empty queue: front –> rear
  3. Full: (rear+1)%length –> front
  4. front point to an empty cell. So at mast it can save length-1 elements.
  5. push only increase rear, so if (rear+1)%length –> front, means rear catch up front, it means full.
  6. pop only increase front, so if front –> rear, means front catch up rear, it means empty.