Define recursive functions

- [Instructor] A common pattern can be found … in the body of many recursive functions. … The body begins with one or more base cases. … Base cases specify how the function should behave … for the simplest inputs. … In other words, … base cases are very simple versions … of the problem you're trying to solve. … The base cases are then followed … by one or more recursive cases. … Recursive cases are more complex versions … of the problem you're trying to solve … and they require one or more recursive calls. … Recursive calls always simplify the original problem. … Recursive functions simplify problems in stages. … For example, say you want to write function … that takes a positive integer as input … and returns the factorial of that number. … You could write a recursive function … and it would look something like this. … The if clause is the base case. … One is the simplest input for this function. … If N is equal to one, … the factorial of N is one. … The else clause is the recursive case. …