Stacks are one of the most powerful yet simple data structures in computer science. From browser history to AI pathfinding, stacks are everywhere — and in 2025, their use cases have only expanded.
What is a Stack?
A stack is a linear data structure that follows the Last In, First Out (LIFO) principle — the last element added is the first one to be removed.
Think of a stack like:
- A pile of books 🧱
- A stack of browser tabs 🌐
Core Stack Operations (With Examples)
| Operation | Description | Python Code |
|---|---|---|
push() |
Adds an element to the top | stack.append(item) |
pop() |
Removes the top element | stack.pop() |
peek() |
Views the top element | stack[-1] |
isEmpty() |
Checks if the stack is empty | len(stack) == 0 |
Python Implementation:
stack = []
# Push
stack.append('A')
stack.append('B')
# Pop
stack.pop() # Removes 'B'
# Peek
top = stack[-1] # 'A'
# Check if empty
print(len(stack) == 0)
Real-World Applications of Stack in 2025
1. Browser History Management
"Back" and "Forward" buttons use stacks under the hood.
2. Undo/Redo in Text Editors
Apps like Google Docs or Figma use stacks to store past actions.
3. Function Call Stack
Every time you call a function, the system uses a stack to manage it.
4. AI Backtracking Algorithms
Used in solving puzzles, pathfinding, and decision trees.
5. Parsing Expressions
Compilers and interpreters use stacks to evaluate expressions.
Visualizing Stack Operations
📊 (Include a simple diagram or use tools like draw.io or Canva to embed visuals)
👉 Want to try it live? Try Online Stack Visualizer
Language-Specific Stack Snippets
🔵 Java:
Stack<Integer> stack = new Stack<>();
stack.push(1);
stack.pop();
🟢 JavaScript:
let stack = [];
stack.push(1);
stack.pop();
Future Trends: Where Stacks Are Headed
- 💡 Used in LLM pipelines for prompt context management
- 💡 Smart contract logic in blockchain platforms
- 💡 UI navigation tracking in mobile app frameworks like Flutter/React Native
Quick Quiz: Test Your Stack IQ
Q: What’s the output of the following code?
s = []
s.append('A')
s.append('B')
s.pop()
print(s[-1])
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