Stacks are one of the most essential data structures you will come across in computer science. Whether you are preparing for technical interviews or learning how real-world programs manage memory and function calls understanding deletion in stack is a must. This concept plays a key role in many practical applications such as undo features browser history and expression evaluation. In this blog we will walk you through what stack deletion means how it works and how you can implement it in popular programming languages like Python C++ and Java.
What is Stack?
A stack is a simple yet powerful data structure that works on the principle of Last In First Out or LIFO. This means that the last element added to the stack is the first one to be removed. Think of a stack as a pile of plates. You place new plates on top and when you need one you take the top plate off first.
You cannot access the plate at the bottom unless you remove all the ones above it. This behavior makes stacks useful in situations where you want to reverse data track states or manage nested function calls. Common applications of stacks include evaluating expressions parsing code and handling browser history or undo features in text editors.
What is Deletion in Stack?
Deletion in stack refers to the process of removing the top element from the stack. This operation is known as the pop operation. Since stacks follow the Last In First Out structure you can only remove the element that was most recently added. If the stack is empty and you try to delete an element an underflow condition occurs which typically results in an error or warning.
This operation is commonly used in algorithms that involve backtracking or reversing actions such as solving mazes and implementing undo functionalities. In short deletion in stack helps you manage data in reverse order allowing you to clean up or retrieve items in the opposite sequence they were added.
Deletion in Stack Algorithm
Check if the stack is empty
Before trying to delete an element always check whether the stack has any elements. If it is empty there is nothing to delete and this should trigger an underflow condition.
Access the top element
Identify the element at the top of the stack. This is the element that will be removed during the deletion process.
Remove the top element
Adjust the stack so that it no longer contains the top element. If you are using an array this means decreasing the top index. If you are using a dynamic data structure like a linked list you will update the pointer to exclude the top node.
Code Examples for Deletion in Stack
Deletion in Stack using Python
stack = [10, 20, 30]
def pop():
if not stack:
print("Stack Underflow! Cannot delete from an empty stack.")
else:
removed = stack.pop()
print(f"Deleted {removed} from stack.")
pop()
print("Current Stack:", stack)Deletion in Stack using C++
#include <iostream>
#include <stack>
using namespace std;
int main() {
stack<int> s;
s.push(10);
s.push(20);
s.push(30);
if (!s.empty()) {
s.pop();
cout << "Top element deleted successfully." << endl;
} else {
cout << "Stack Underflow! Cannot delete from an empty stack." << endl;
}
if (!s.empty()) {
cout << "Current Top Element: " << s.top() << endl;
}
return 0;
}
Applications of Stack Deletion
- Backtracking algorithms like solving mazes or puzzles
- Undo and redo functionality in software applications
- Function call management during recursive operations
- Parsing expressions in compilers and interpreters
- Managing browser history or navigation states
Frequently Asked Questions (FAQs)
What is deletion in stack?
Deletion in stack means removing the top element using the pop operation. It follows the Last In First Out principle so the most recently added item is the first one to be removed.
What is the time complexity of deletion in a stack
The time complexity of deletion in a stack is O(1).
Can we delete elements from the bottom of the stack
No you cannot delete elements from the bottom directly. Stacks only allow access to the top element. To delete something from the bottom you must first remove all the elements above it.