? Java Recursion

? Quick Overview

Recursion in Java is a programming technique where a method calls itself to solve a problem by breaking it into smaller subproblems. Each recursive call works on a reduced version of the original problem until a base condition is met.

? Key Concepts

• Recursive method must call itself
• Every recursion must have a base condition
• Each call uses stack memory
• Problem is divided into smaller subproblems

? Syntax / Theory

A recursive method in Java consists of two essential parts:

• Base Case: Condition to stop recursion
• Recursive Case: Method calling itself

// Recursive method syntax in Java
returnType methodName(parameters) {
// base condition
if(condition) {
return value;
}
// recursive call
return methodName(modifiedParameters);
}

? Code Example(s)

// Java program to calculate factorial using recursion
class Factorial {
static int factorial(int n) {
// base condition to stop recursion
if(n == 0) {
return 1;
}
// recursive call
return n * factorial(n - 1);
}

public static void main(String[] args) {
int result = factorial(5);
System.out.println(result);
}
}

? Live Output / Explanation

?️ Interactive Demo: The Call Stack