Recursion: A Picture is Worth 1,500 Words

What is Recursion?

The process in which a function calls itself directly or indirectly is called recursion and the corresponding function is called a recursive function. Using a recursive algorithm, certain problems can be solved quite easily.

Need of Recursion:

Recursion is an amazing technique with the help of which we can reduce the length of our code and make it easier to read and write. It has certain advantages over the iteration technique which will be discussed later. A task that can be defined with its similar subtask, recursion is one of the best solutions for it. For example; The Factorial of a number.

Sequence of steps of a Recursive function:

1. Initialize the algorithm. Recursive programs often need a seed value to start with. This is accomplished either by using a parameter passed to the function or by providing a gateway function that is nonrecursive but that sets up the seed values for the recursive calculation.
2. Check to see whether the current value(s) being processed match the base case. If so, process and return the value.
3. Redefine the answer in terms of a smaller or simpler sub-problem or sub-problems.
4. Run the algorithm on the sub-problem.
5. Combine the results in the formulation of the answer.
6. Return the results.