Recursion is a programming technique where a function calls itself to solve smaller instances of the same problem. It’s elegant but tricky for beginners—let’s break it down with clear examples in Python, JavaScript, and Java.

What is Recursion?

You’re Not a Senior Developer Until You Have These 8 Traits

Recursion solves problems by:

  1. Base Case – The simplest scenario (stops recursion).
  2. Recursive Case – Breaking the problem into smaller subproblems.

Example: Factorial Calculation

See document.querySelector() vs. getElementById(): Which is Faster?

1. Python

def factorial(n):
if n == 1: # Base case
return 1
return n * factorial(n - 1) # Recursive case

print(factorial(5)) # Output: 120

2. JavaScript

function factorial(n) {
if (n === 1) return 1; // Base case
return n * factorial(n - 1); // Recursive case
}

console.log(factorial(5)); // Output: 120

3. Java

public class Main {
static int factorial(int n) {
if (n == 1) return 1; // Base case
return n * factorial(n - 1); // Recursive case
}

public static void main(String[] args) {  
    System.out.println(factorial(5));  // Output: 120  
}  
}

Another Example: Fibonacci Sequence

Python

def fibonacci(n):
if n <= 1: return n # Base case
return fibonacci(n - 1) + fibonacci(n - 2)

print(fibonacci(6)) # Output: 8

JavaScript

javascript
function fibonacci(n) {
if (n <= 1) return n;
return fibonacci(n - 1) + fibonacci(n - 2);
}

console.log(fibonacci(6)); // Output: 8

3. Java

public class Main {
static int fibonacci(int n) {
if (n <= 1) return n;
return fibonacci(n - 1) + fibonacci(n - 2);
}

public static void main(String[] args) {  
    System.out.println(fibonacci(6));  // Output: 8  
} 
}

When to Use Recursion?

Tree/Graph Traversal (e.g., binary search trees).
Divide & Conquer Algorithms (e.g., mergesort).
Problems with repetitive subproblems (but watch for inefficiency!).

Watch Out For:

Missing base case → Stack Overflow!
Exponential time complexity (e.g., naive Fibonacci).

Final Challenge

Try implementing a recursive sum of numbers from 1 to n in all three languages!

Recent Posts

What is a QR Code And How to Create One

QR codes have evolved from a niche tracking technology to an indispensable digital connector, seamlessly…

7 days ago

Will AI Replace Software Developers?

Artificial Intelligence (AI) has made remarkable progress in recent years, transforming industries such as healthcare,…

2 weeks ago

Can Tech Really Solve Climate Change—Or Is It Just Greenwashing?

Climate change is one of the most pressing challenges of our time, with rising global…

3 weeks ago

The Inevitable Rise of Transhumanism

In the last few decades, technology has become so embedded in our daily lives that…

3 weeks ago

Drones 101: What They Are & How They Work

In recent years, drones have become more than just cool gadgets or tools for tech…

4 weeks ago

React Native vs. Flutter: Which is Best to Build Mobile Apps in Abuja?

Looking to build mobile apps in Abuja? Choosing the right framework is crucial for performance,…

1 month ago