What is recursion in programming?

Recursion in programming refers to a specific technique where a function calls itself, either directly or indirectly, to solve a problem. This capability allows developers to tackle problems by breaking them down into smaller subproblems that are easier to solve. The function continues to call itself with modified parameters until it reaches a base case, which is a stopping condition that prevents further calls. This approach is particularly effective for problems that can naturally be divided into similar smaller problems, such as calculating factorials, traversing data structures like trees and graphs, or implementing algorithms like quicksort and mergesort.

While other methods of programming, such as loops or iterative algorithms, may serve similar purposes in terms of repetitive tasks, they are not the same as recursion. Unlike recursion, which involves a self-referential process, iterative algorithms use constructs like 'for' or 'while' loops to repeat a block of code without structural function calls. Thus, the essence of recursion lies in its self-calling feature, which makes it a distinctly different approach in the realm of programming logic.