Recursion - Python

Recursion

Recursion is the process of calling the function that is currently executing. It is legal for one function to call another; it is also legal for a function to call itself. An example of recursive function to find the factorial of an integer.

Factorial of a number is the product of all the integers from 1 to that number. For example, the factorial of 6 (denoted as 6!) is 1*2*3*4*5*6 = 720.

#An example of a recursive function to

#find the factorial of a number

def calc_factorial(x):

"""This is a recursive function to find the factorial of an integer"""

if x == 1:

return 1

else:

return (x * calc_factorial(x-1))

num = 4

print("The factorial of", num, "is", calc_factorial(num))

Output:

The factorial of 4 is 24

The Advantages of recursion

·        Recursive functions make the code look clean and elegant.

·        A complex task can be broken down into simpler sub-problems using recursion.

·        Sequence generation is easier with recursion than using some nested iteration.

The Disadvantages of recursion

·        Sometimes the logic behind recursion is hard to follow through.

·        Recursive calls are expensive (inefficient) as they take up a lot of memory and time.

·        Recursive functions are hard to debug.