When it comes to data structures, there are various types that serve different purposes. One common type of data structure is the stack. A stack is a Last-In-First-Out (LIFO) data structure, meaning that the last element added to the stack is the first one to be removed.
What is a Stack?
A stack is an abstract data type that represents a collection of elements with two main operations: push and pop. The push operation adds an element to the top of the stack, while the pop operation removes and returns the topmost element.
How Does a Stack Work?
A stack follows a simple principle: Last-In-First-Out. Imagine it as a stack of plates or books – you can only add or remove elements from the top. The last book you put on the stack will be the first one you take off.
Pushing Elements onto a Stack
To push an element onto a stack, you simply add it to the top. This operation increases the size of the stack by one. Here’s an example:
<ul> <li>Push "A" onto the stack</li> <li>Push "B" onto the stack</li> <li>Push "C" onto the stack</li> </ul>
Popping Elements from a Stack
To pop an element from a stack, you remove and return the topmost element. This operation decreases the size of the stack by one. Here’s an example:
<ul> <li>Pop the top element from the stack - returns "C"</li> <li>Pop the top element from the stack - returns "B"</li> <li>Pop the top element from the stack - returns "A"</li> </ul>
Common Use Cases
Stacks are widely used in computer science and programming. Some common use cases include:
- Function call stacks: Storing information about function calls and their local variables.
- Expression evaluation: Evaluating mathematical expressions using the postfix notation.
- Undo/Redo operations: Keeping track of changes to support undoing and redoing actions.
- Browser history: Maintaining a history of visited web pages for backward navigation.
A stack is a Last-In-First-Out (LIFO) data structure, where elements are added and removed from the top. It follows a simple principle of Last-In-First-Out, similar to stacking plates or books. Stacks have various applications in computer science, making them an essential concept to understand.
Now that you have a better understanding of stacks, you can begin exploring their implementation in different programming languages.