Stacks and Queues are features in programing language that assist the user in solving any arising problems in the program. Although both stack and queue are vastly categorized under the data structures that are non-primitive, they are different from each other in several aspects.
Stack vs Queue
The main difference between Stack and Queue is that, in the case of the stack, deletion of element takes place from one end and addition of element takes place in the ordered list itself that known as TOS. On the other hand, in the case of the queue, deletion of elements and insertion of elements take place from the same end.
The stack can be described as a linear data structure that can be said non-primitive. From one end, the pre-established element is removed and new elements are added in this ordered list which is known as the TOS or the top of the stack. The stack can exhibit the performance of basic operations such as PUSH and POP.
The queue is also considered as the non-primitive type of data structure that is linear. It is a gathering of elements that are similar to each other. It has two ends rare and front ends where elements are inserted or deleted respectively. The queue can exhibit the performance of basic operations such as enqueue and dequeue.
Comparison Table Between Stack and Queue
| Parameters for comparison | Stack | Queue |
| Working principle | The working principle associated with the stack is considered as LIFO or last in the first out type of list. | The working principle associated with the queue is considered to be first in first out list type or FIFO. |
| Usage of pointers and operations | The number of pointers used in the stack is one. The operations performed in this data structure are push and pop. | The number of pointers used in the queue is two. The operations performed in this data structure are enqueue and dequeue. |
| Structure | In this data structure of stack, elements can be inserted with the utilization of one and can be deleted using the same end. | In the case of the queue, the rear end is concerned with the insertion and the front end is concerned with the deletion of elements. |
| Variants | Unlike queue, the stack data structure is not associated with variants. The implementation associated with it is simpler. | This data structure has variants such as priority queue, circular queue, and doubly ended queue. Its implementation is comparatively complex. |
| Examination of condition | Examination of an empty condition associated with the stack is Top == – 1. Examination of the full condition of the stack is Top == Max – 1. | Examination of empty condition is Front == -1|| Front ++ Rear + 1 and examination of full condition is Rear == Max – 1. |
What is Stack?
The last element added to the stack will be deleted as insertion or deletion is executed from the top of the stack. It is known as the last-in-first-out type of list or LIFO due to this purpose. There are several implementations of the stack such as undo in the word processor, java virtual machine, a compiler’s parsing, printers’ PostScript language, web browser’s back button, incorporating function calls in compilers, and others. Implementation of the stack can be done in two manners such as static implementation and dynamic implementation.
Stack in developed in static implementation with the help of arrays. Though the static implementation is known to be effortless, it permits the declaration of the stack size only while designing the program after which the verification of size cannot be done. Static implementation is not considered to have high efficiency associated with the utilization of memory. On the other hand, dynamic implementation is also known as linked list representation. Pointers are used for implementing data structure with stack type. As an example, we may say that when the wrapper of biscuits is torn on one end, the biscuits can be taken out from there (popping) and from this end, biscuits can be put back (pushing).
What is Queue?
This is considered to be FIFO or first in first out type of list. The implementation of the queue can be branched into static implementation and dynamic implementation. In a static implementation, when arrays are used for implementing queue and the definite number of elements to be stored in the queue should be assured beforehand. This is done as the array’s size has to be assured before processing or during designing. The front of the queue comprises the starting of the array and the rear of the queue comprises the array’s final location.
The dynamic implementation has a linked representation where the data field is present. Linked representation’s merit becomes evident when an element is required to get inserted or deleted in the middle of groups comprising other elements. The queue can be applied in several ways such as traffic analysis, data buffers, determination of the number of cashiers required in a supermarket, allotting requests on shared resources like processor or printer, asynchronous transfer of data, and several others. As an example, we may say that when we wait for getting serviced then we form a queue for getting services that can be considered as a queue.
Main Differences Between Stack and Queue
- The working principle of the stack is known to be the LIFO type of list whereas the working principle of the queue is the FIFO type of list.
- Usage of pointers in case of the stack is one and in case of the queue, it is two.
- In the case of the stack, elements can be inserted as well as deleted from the very same end. In the case of the queue, the rear end is associated with addiction and the front end is associated with elements’ deletion.
- Stack does not have variants whereas queue has variants.
- The implementation of the stack is simpler but the implementation of the queue is more complex than that of the stack.
Conclusion
Thus it can be concluded by saying that stack and queue are both non-primitive but they are distinctly different from each other based on various parameters. Push and pop are operations performed in the stack and enqueue and dequeue are operations performed in the queue. In the case of the stack, the examination of the full condition can be given as Top == Max – 1 whereas, in the queue, the examination of the full condition can be given as Rear == Max – 1. The examination of empty condition in case of the stack is Top == – 1. On the other hand, the examination of empty condition in case of queue is Front == -1|| Front ++ Rear + 1.
References
- https://www.sciencedirect.com/science/article/abs/pii/S0305054818301977
- https://ieeexplore.ieee.org/abstract/document/8560943/