Now that we are familiar with functions, let's have a review on the most important concept using a function: recursion.
We'll cover the following
What Is Recursion?
Recursion is when a function calls itself again and again until it reaches the base condition.
Parts of a Recursion
There are two parts of recursion:
base condition and
For instance, take the example of a Factorial function.
Factorial(!) of a number n is the product of all positive numbers from our chosen number n down to 1.
factorial(n) = 1 if n <= 1 #base case factorial (n) = n * factorial(n-1) #recursive function
Let’s use an example of factorial of 5.
5! = 5 × 4! = 5 × 4 × 3! = 5 × 4 × 3 ×2! = 5 × 4 ×3 ×2 ×1 = 120
Below is the call to the function factorial given 5 as a parameter to the function. factorial(5)
It is calculated recursively in the following manner: