Before Stack and Queue differences it is better to understand the concept of Data type in programming which state that Data types are the type of data in which variables are created to store data. Primarily there are two types of data types which are Primitive and Non Primitive data type where Primitive data types are predefined types of data, which are supported by the programming language while Non-primitive data types are not defined by the programming language, but are instead created by the programmer.
Now Stack and Queue both are the non-primitive data structures but on the basis of internal implementation we can list down some the main differences between both of these data structures which are as below:
| Sr. No. | Key | Stack | Queue |
|---|---|---|---|
| 1 | Internal Implementation | Stack is internally implemented in such a way that the element inserted at the last in stack would be the first element to come out of it.So stack follows LIFO (Last in and First out). | On other hand Queue is implemented in such manner that the element inserted at the first in queue would be the first element to come out of it.So queue follows FIFO (First in and First out). |
| 2 | Target element | In case of Stack operations on element take place only from one end of the list called the top. | In case of Queue operations on element i.e insertion takes place at the rear of the list and the deletion takes place from the front of the list. |
| 3 | Label and Flag | In stacks only one flag is maintained to access the list which always points to the last element present in the list. | While in case of queue two flags are maintained to access the list. The front flag always points to the first element inserted in the list and is still present, and the rear flag always points to the last inserted element. |
| 4 | Operation | In Stack operations termed as Push and Pop. | While in case of Queue operations termed as Enqueue and dequeue. |
| 5 | Implementation | Stack does not have any variant and thus do not implemented further. | On other hand Queue has variants like circular queue, priority queue, doubly ended queue. |
| 6 | Complexity | As per above points the Stack is more simpler than Queue. | On other hand Queue is more complex as compare to Stack. |