How does "recursion" differ from iteration?

Recursion is a programming technique where a function calls itself in order to solve a problem. This approach often breaks down a complex problem into smaller, more manageable subproblems, allowing for solutions to be built up from these components. The self-referential nature of recursion is its defining characteristic, which enables it to efficiently handle tasks like traversing data structures or solving mathematical problems that can be defined in terms of themselves.

By contrast, iteration typically relies on loops to repeat a block of code until a certain condition is met, which does not involve a function calling itself. It operates through constructs like for or while loops, making it a different technique for problem-solving entirely.

Understanding this distinction highlights the unique advantages of recursion in scenarios where a problem can be naturally divided into similar subproblems, making it a powerful tool in many algorithms, particularly in tasks that involve tree and graph traversal or algorithms like quicksort and mergesort.