Recursion and Computer Science

Recursion is the solving of large-scale problems by solving small-scale problems of similar structure. There is always one or more "base cases", which are cases that do not need to be broken down further. A recursive solution must repeatedly break down the problem until one of these is reached. Some people may struggle with the idea of recursion, so here is a simple visual explanation of it:

The biggest doll contains similar smaller dolls within it, which contain dolls of their own, until the smallest doll is reached. Once that doll is "solved", the process goes backwards and "solves" previous dolls until the first one is finally reached and "solved" through the smaller solutions. This is a great concept for computer scientists to put to use because it goes above and beyond looping structures and can solve complex problems with elegance and efficiency. Although many or all loops can be converted into recursive functions with a little bit of work, it is difficult and sometimes impossible to convert recursive functions into loops. Recursion allows the programmer to solve problems of unknown nested depth by solving sub-problems of sub-problems of sub-problems with changing parameters - something that loops cannot do because of their strict and repetitious structure.