A stack is a fundamental linear data structure used for storing data. It follows the LIFO (Last In First Out) strategy, which means that the element inserted last will come out first. A pile of plates kept on top of each other is a real-life example of a stack. The plate that we put last is on the top, and since we remove the plate at the top, we can say that the plate that was put last comes out first. It can be implemented through an array or linked lists. Some of its primary operations are push(), pop(), top(), isEmpty(), size(), etc. In order to manipulate the stack, certain operations are provided to us. When we insert an element into the stack, the operation is known as the push operation, while when we remove an element from the stack, the operation is known as the pop operation. If we try to pop from an empty stack, it is known as underflow, and if we try to push an element in a stack that is already full, it is known as overflow.
Primary Stack Operations:
push(int data): This operation inserts an element into the stack.
pop(): This operation removes an element from the top of the stack and returns it.
Auxiliary Stack Operations:
top(): This operation returns the last inserted element at the top of the stack without removing it.
size(): This operation returns the size of the stack, i.e., the total number of elements present in the stack.
isEmpty(): This operation indicates whether the stack is empty or not.
isFull(): This operation indicates whether the stack is full or not.
Types of Stacks:
Register Stack: This type of stack is a memory element present in the memory unit and can handle a small amount of data only. The height of the register stack is always limited as the size of the register stack is very small compared to memory.
Memory Stack: This type of stack can handle a large amount of memory data. The height of the memory stack is flexible as it occupies a large amount of memory data.
What is Meant by Top of the Stack?
The pointer through which the elements are accessed, inserted, and deleted in the stack is called the top of the stack. It is the pointer to the topmost element of the stack.
Application of Stack Data Structure:
Stack is used for evaluating expressions with operands and operations.
Matching tags in HTML and XML.
Undo function in any text editor.
Infix to Postfix conversion.
Stacks are used for backtracking and parenthesis matching.
Stacks are used for conversion of one arithmetic notation to another arithmetic notation.
Stacks are useful for function calls, storing the activation records, and deleting them after returning from the function. It is very useful in processing function calls.
Stacks help in reversing any set of data or strings.
Application of Stack in Real Life:
CD/DVD stand.
Stack of books in a book shop.
Undo and Redo mechanism in text editors.
The history of a web browser is stored in the form of a stack.
Call logs, e-mails, and Google photos in any gallery are also stored in the form of a stack.
YouTube downloads and notifications are also shown in LIFO format (the latest appears first).
Advantages of Stack:
Stack helps in managing data that follows the LIFO technique.
Stacks can be used for systematic memory management.
It is used in many virtual machines like JVM.
When a function is called, the local variables and other function parameters are stored in the stack and automatically destroyed once returned from the function. Hence, efficient function management.
Stacks are more secure and reliable as they do not get corrupted easily.
Stacks allow for efficient memory allocation and deallocation, which can lead to better performance and memory management in programs. Additionally, since the stack follows the LIFO strategy, it can be used to implement certain algorithms and data structures such as recursion and depth-first search. This can simplify the coding process and make it easier to understand and debug code.
Another advantage of using a stack is that it can provide automatic cleanup of objects. This is especially useful in languages that do not have automatic garbage collection, as it can help prevent memory leaks and improve the overall performance of the program.
Overall, the use of stacks can lead to more efficient and reliable code, better memory management, and simpler implementation of algorithms and data structures. However, it is important to keep in mind the limitations of stack memory and avoid stack overflow errors in programming.
