print ("Please enter a positive integer.") The program defines a function sum_of_natural_numbers that takes an integer n as input and calculates the sum of the first n natural numbers using recursion.

\tdigit sum. Example: input = 123 -> output = 6''') #Recursive function designed to calculate the digit some of a given postive integer.

Recursion is the process in which a function calls itself directly or indirectly. The corresponding function of recursion is called the recursive function. Some examples of recursion include DFS of ...