A stack is a linear data structure that follows the Last In First Out (LIFO) principle, which means that the last element added to the stack will be the first element removed from it.
The stack is a collection of elements or items that are stored and accessed in a particular way. Elements can be added to the stack using a push operation, and removed from the stack using a pop operation. The push operation adds an element to the top of the stack, and the pop operation removes the element from the top of the stack.
The stack data structure is commonly used in programming languages and applications to store and manage information. For example, it is used in the execution of programs to keep track of function calls, and in the handling of recursive algorithms. It is also used in the implementation of undo/redo functionality in applications, where a stack is used to keep track of the sequence of user actions that can be undone or redone.
Types of stack data structure.
There are several types of stack data structures, including:
Array-based stack: This type of stack is implemented using an array data structure, where the elements are stored in contiguous memory locations. The operations on this stack are performed using the index of the last element.
Linked list-based stack: In this type of stack, elements are stored in nodes, and each node has a pointer to the next node. The top of the stack is represented by the first node in the linked list.
Dynamic stack: A dynamic stack is a type of stack that can grow or shrink in size during runtime, depending on the number of elements that are pushed or popped from it. This type of stack is often implemented using a linked list.
Fixed stack: A fixed stack is a type of stack that has a fixed size, and its capacity cannot be changed during runtime. This type of stack is often implemented using an array.
Priority stack: A priority stack is a type of stack that is used to store elements with priorities, and the elements are sorted based on their priority value. This type of stack is often used in scheduling and resource allocation applications.
Double-ended stack: A double-ended stack, also known as a deque, is a type of stack that allows elements to be inserted or removed from both ends of the stack. This type of stack is often used in algorithms such as breadth-first search and sliding window problems.
These are some of the most common types of stack data structures used in computer science.
Uses of stack data structure.
Stacks are commonly used in computer science and programming for various applications, some of which are:
Function call/return: Stacks are used to keep track of function calls and their return values in many programming languages.
Expression evaluation: Stacks can be used to evaluate postfix expressions, infix expressions, and prefix expressions.
Memory management: The stack is used for storing local variables, function parameters, and return addresses in computer memory.
Parsing: Stacks can be used in parsing algorithms such as recursive descent parsing and LR parsing.
Undo/Redo: Stacks can be used to implement undo/redo operations in software applications.
Backtracking: Stacks can be used to keep track of decisions made during a recursive search or backtracking algorithm.
Browser history: Browsers use a stack data structure to maintain a history of visited pages, allowing users to navigate back and forth between pages.
Implementing data structures: Stacks can be used to implement other data structures like queues, trees, and graphs.
Overall, stacks are a very useful data structure that can be used in many different applications, especially when it comes to organizing and manipulating data in a Last-In-First-Out (LIFO) manner.