Computer science sophomores learn that recursion can neatly solve complex problems, e.g., Hanoi rings, wildcard handling, and parsing. In practice, however, recursion can be problematic for several reasons. First of all, it’s complicated. Every recursion-based algorithm can be expressed as an iterative one. Thus, instead of having a function call itself repeatedly until a certain condition becomes true, you can use a while statement or a similar simple construct. Recursion is less intuitive for an average programmer?iteration is much more common in everyday programming. Secondly, iteration is significantly more efficient than recursion because it avoids the overhead of a full-blown function call (note that recursive calls are never inlined). Furthermore, while the number of iterations is virtually unlimited, i.e., you can have a loop that executes infinitely, every operating system limits the number of recursive calls allowed. The limit depends on the available stack memory and other factors such as system load, the size of the function’s argument list, etc. Thus, the behavior of a large number of recursive calls is unpredictable: such a function may succeed or cause a runtime crash, depending on the system’s state. Recursion is cute and can impress your college instructor. Still, in real world programming, it should be rarely used, if at all.