What is recursion in programming?

Recursion is a programming technique that involves solving a problem by breaking it down into smaller and simpler sub-problems, and then solving each sub-problem by applying the same technique recursively. In other words, recursion is a process in which a function calls itself as a subroutine.

The main advantage of recursion is that it allows you to write complex algorithms in a simpler, more elegant way. It is particularly useful for problems that have a recursive structure, such as sorting and searching algorithms, tree traversals, and mathematical computations.

However, recursion can also be dangerous if not used correctly. It can lead to infinite loops, stack overflows, and other issues if the base case (i.e., the condition that stops the recursion) is not well-defined or if the recursion depth is too large.