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CHAPTER 4: QUEUE, CODE SEGMENT Picture1, yuna(slide3), yuna(slide22),…

- - - - EXAMPLE OF QUEUE OPERATION (LINEAR IMPLEMENTATION)
        
        EXAMPLE 1
        
        create (Q)
        
        front = 0
        rear = 0
        
        enqueue (Q,20)
        
        front = 0
        rear = 1
        
        enqueue (Q,40)
        
        front = 0
        rear = 2
        
        EXAMPLE 2
        
        create (S)
        
        front = 0
        rear = 0
        
        enqueue (S,11)
        
        front = 0
        rear = 1
        
        enqueue (S,22)
        
        front = 0
        rear = 2
        
        enqueue (S,33)
        
        front = 0
        rear = 3
        
        Example 3
        
        enqueue(K,20)
        
        front = 0
        rear = 1
        
        enqueue (K,23)
        
        front = 0
        rear = 2
        -enqueue (K,30)
        
        front = 0
        rear = 3
        
        dequeue (K)
        
        front = 1
        rear = 3
        
        dequeue (K)
        
        front = 2
        rear = 3
    - - Linear implementation
        
        contains the elements in a sequential manner.
        
        Example
        
        Array
        
        Linked list
      - Circular implementation
        
        also a linear data structure
        
        last element of the Queue is connected to the first element
        
        creating a circle
        
        Example
        
        Array
  - - - The picture above show the code segments for enqueue item
    - - To check if queue is full or empty:
        
        If rear = 0, queue is empty where no data in queue
        
        If rear = 4, whereas the size for the list, so that the queue is full.
        
        The picture below show how to to check queue whether is full or empty.
    - - -This picture show how to dequeue item:
    - - Implement queue using array
        (Code Segment)
        Creare queue
        void createQueue (qQueue *q)
        {
        q-.front = 0;
        q-.rear = 0;
        }
        
        Memory Drawing
      - athirah (slide 11)
        
        IMPLEMENT QUEUE USING ARRAY
        
        Example of data structure declaration for array implementation of queue.
        
        Code segment
        
        Declare structure of queue
        typedef struct QUEUE { int front, rear; int list [4]; } qQueue;
        
        Memory drawing
  - - - Gibson (slide 17)
        Front: Get the front item from queue.
        Rear: Get the last item from queue.
        enQueue(value) This function is used to insert an element into the circular queue
    - - Linear Implementation Using Linked List
        Each node contains two parts, data part and link part.
        Front pointer contains starting element address and rear pointer contains last element of the queue.
        Each element of the queue points to the next element in the memory.
      - Insertions and deletions are done at the rear and front respectively. If the front and the rear is NULL then the queue is empty.
    - - IMPLEMENT QUEUE USING ARRAY
        
        JAZRIN ( SLIDE 20)
        
        Check queue empty :
        int empty(qQueue *q)
        {
        if(q- > rear == q- >front)
        return (1);
        else
        return(0);
        }
        
        If rear = front, that’s mean queue is empty.
        ( no data in the queue)
        
        Check queue full :
        int full(qQueue *q)
        {
        if((q- > rear + 1) % 4) == q- >front)
        return (1);
        else
        return(0);
        }
        
        If (rear +1 )% 4 = front, that’s mean queue is full.
        ( cant enqueue data anymore, unless you delete some data in the queue)
    - - A circular queue is an extended version of a linear queue as it follows the First In First Out principle with the exception that it connects the last node of a queue to its first by forming a circular link. Hence, it is also called a Ring Buffer.
- - - - Circular
      - Linear
    - - Linked list
      - Array
- - - - This picture show how the operation of queue work