What is recursion in programming?

Recursion in programming is a technique where a function calls itself directly or indirectly, allowing the code to loop through operations until it reaches a base condition. This base condition is crucial as it stops the recursive calls from happening infinitely, thereby preventing a potential stack overflow error. Recursive functions are especially useful for tasks that can be broken down into similar subtasks, such as sorting algorithms (e.g., quicksort, mergesort), navigating through hierarchical structures (like file systems or certain types of data structures like trees and graphs), and solving certain types of mathematical problems (e.g., calculating factorial numbers, Fibonacci series).

In essence, a recursive function typically consists of two main parts:
1. Base Case: This is the condition under which the function will stop calling itself, preventing an infinite loop.
2. Recursive Case: This is the part of the function where the recursion (self-call) occurs. It moves the problem towards the base case, ideally reducing the complexity or size of the problem with each recursive call.

Example in Python:

def factorial(n):

if n == 1: # Base case

return 1

else:

return n * factorial(n-1) # Recursive case

This example calculates the factorial of a number `n` by calling itself with `n-1` until it reaches the base case `n == 1`.

Recursion can be a powerful tool in programming, offering elegant solutions to complex problems, but