Recursion Function In Python

What is recursion?
Recursion Function In Python:

The recursion is a process where function calls itself to perform a task. The calling of function itself is done repeatedly until certain condition met. Recursion is process in which function calls directly or indirectly.

Advantages of Recursion Function:

1.    Breaking down a function into smaller sub problems to reach to the base problem.

2.    It is very simpler than other nested functions.

3.    Code is very simple and effective than other normal functions.

Syntax of Recursive Function:

def function_name():  # Function definition

          Statement

          Statement

          Recursive function_call() # Recursion

Function_name() # Function call

Def keyword is used to define the function. Function_name is the name of function given by user. Function body includes statements and recursive function call. The function call itself until certain condition satisfy. Then function is called to invoke the user defined function and function body executed.

For example,

Factorial of given number using Recursive function in Python

print("Demonstration of Recursive Function in Python")

print("______________________________________\n")

def factorial(n):  #function definition

    if n==0:

        return 1

    else:

        return n*factorial(n-1) # Recursion

n=int(input("Enter number:"))

print(f"The factorial of {n} is:",factorial(n)) # Function call

 

Output:

Demonstration of Recursive Function in Python

_____________________________________________

 

Enter number:5

The factorial of 5 is: 120

 

In above example factorial is user defined function with argument n. User input is stored into n to calculate factorial of n. Function body have processing statements which have conditional statement. If n is exactly equals to 0. Then compiler will return 1. If condition becomes false means n is greater than 0 then the function calls itself with argument n-1 until condition satisfy. This process is done repeatedly until condition satisfy.