What data structure allows insertion and removal of elements only at one end, following a last-in-first-out principle?

What data structure allows insertion and removal of elements only at one end, following a last-in-first-out principle?

• A. Queue
• B. Stack
• C. List
• D. Array

Answer: (B)

The data structure that allows for insertion and removal of elements only at one end, following a last-in-first-out (LIFO) principle, is indeed a stack. In a stack, the last element added to the structure is the first one to be removed, similar to a stack of plates where you can only take the top plate off or add a new one on top. When you push an element onto the stack, it goes on top of the existing elements. When you pop an element, the most recently added one is removed first. This behavior is crucial for certain algorithm applications, such as navigating back in a web browser or handling function calls in programming languages, where the most recent function call must be resolved first. In contrast, other data structures like queues allow for operations at both ends, with a first-in-first-out (FIFO) principle, while lists and arrays do not enforce this specific insertion and removal constraint regarding the positioning of elements. Thus, the defining characteristics of a stack make it the correct answer for this question.

The data structure that allows for insertion and removal of elements only at one end, following a last-in-first-out (LIFO) principle, is indeed a stack. In a stack, the last element added to the structure is the first one to be removed, similar to a stack of plates where you can only take the top plate off or add a new one on top.

When you push an element onto the stack, it goes on top of the existing elements. When you pop an element, the most recently added one is removed first. This behavior is crucial for certain algorithm applications, such as navigating back in a web browser or handling function calls in programming languages, where the most recent function call must be resolved first.

In contrast, other data structures like queues allow for operations at both ends, with a first-in-first-out (FIFO) principle, while lists and arrays do not enforce this specific insertion and removal constraint regarding the positioning of elements. Thus, the defining characteristics of a stack make it the correct answer for this question.