generatorloha.blogg.se - Enqueue dequeue c linked list stack

#ENQUEUE DEQUEUE C LINKED LIST STACK UPDATE#
#ENQUEUE DEQUEUE C LINKED LIST STACK FULL#
#ENQUEUE DEQUEUE C LINKED LIST STACK SOFTWARE#

If it is NOT EMPTY, then increment the front value by one ( front++ ).If it is EMPTY, then display an error and terminate the function.If it is NOT FULL, then increment the rear value by one ( rear++ ) and set queue = value.If it is FULL, then display an error and terminate the function.

#ENQUEUE DEQUEUE C LINKED LIST STACK FULL#

Check whether the queue is FULL ( rear = SIZE - 1).

Int front = -1, rear = -1 Enqueue Operation

Define two integer variables front and rear and initialize both with ‘-1’.

Create a one dimensional array with the above defined SIZE.

For simplicity, we will create a queue with an array. if(rear = SIZE-1)Ī queue can be created using both an array or through a linked list. This prevents any error if more space cannot be allocated for the next item. The overflow condition checks if the queue is full (or more memory is available) before enqueueing any element. The underflow condition checks if there exists any item before popping from the queue. We must implement check conditions to see if we are not adding or deleting elements more than it can maximum support. Overflow and Underflow ConditionsĪ queue may have a limited space depending on the implementation. The rear pointer always points to the position where an element would be enqueued next. The front pointer always points to the position where an element would be dequeued next.

#ENQUEUE DEQUEUE C LINKED LIST STACK UPDATE#

These pointers update continuously and keep a check on the overflow and underflow conditions. To efficiently add or remove data from the queue, two special pointers are used which keep track of the first and last element in the queue. The element always gets removed from the front of the queue. The Dequeue is used to remove an element from the queue. The element always gets added to the end of the current queue items.

The Enqueue is used to add an element to the queue. The two primary operations in a queue are the enqueue and the dequeue operation: Enqueue Operation The first person to enter leaves first.Ī ticket counter can be an example where the people standing in the queue get their tickets one by one and leave the queue. A person may join the queue from the end and may leave tit from the front. Let us implement the queue data structure using C++.Queues can be visualised like a real-life queue of people.

As a result, after the first dequeue, the front pointer now will be moved ahead t0 the next location which is 1. 1 happens to be the first element removed from the queue. Thus the first element entered in the queue i.e. As the front pointer is at 0, the element that is deleted is 1. Next, we delete the element pointed by the front pointer. In the following figure, we add element 3 and move the rear pointer by 1.Īt this point, the rear pointer has value 2 while the front pointer is at the 0 th location. In the next figure, we add element 2 to the queue by moving the rear pointer ahead by another increment. Next, we add 1 to the queue and as a result, the rear pointer moves ahead by one location. This is an empty queue and thus we have rear and empty set to -1. Next, we will see a detailed illustration of insertion and deletion operations in queue. Increment the ‘front’ to point to the next accessible data.Else, the access element is pointed out by ‘front’.If empty, display an underflow error and exit.Add an element to the location pointed by ‘rear’.ĭequeue operation consists of the following steps:.If full, produce overflow error and exit.In this process, the following steps are performed: peek: Gets an element at the front of the queue without removing it.An item is removed or de-queued always from the front of the queue. DeQueue: Removes an item from the queue.Addition of an item to the queue is always done at the rear of the queue. The queue data structure includes the following operations: When the front is null, then the queue is empty. When the rear pointer value is size-1, then we say that the queue is full. The operation to remove/delete elements from the queue is called “dequeue”. The “front” end pointer is the place from where the elements are removed from the queue. The operation of adding /inserting elements in the queue is called “enqueue”. The “rear” end pointer is the place from where the elements are inserted in the queue. When the queue is empty, then both the pointers are set to -1.

#ENQUEUE DEQUEUE C LINKED LIST STACK SOFTWARE#

In software terms, the queue can be viewed as a set or collection of elements as shown below.