Day 20 : Python Program to Find Sum of Digit of a Number using Recursion

 

def sum_of_digits(number):

    if number == 0:

        return 0

    return (number % 10) + sum_of_digits(number // 10)

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

result = sum_of_digits(abs(number))  

print(f"The sum of the digits of {number} is {result}.")

Code Explanation:

1. Function Definition

def sum_of_digits(number):

def: Declares a new function.

sum_of_digits: The name of the function, which computes the sum of the digits of a number.

number: Input parameter representing the number whose digits will be summed.

2. Base Case for Recursion

    if number == 0:

        return 0

if number == 0:: Checks if the number is 0.

This is the base case for recursion, ensuring the recursion eventually stops.

return 0: Returns 0 if the number is 0. This stops the recursive calls.

3. Recursive Case

    return (number % 10) + sum_of_digits(number // 10)

number % 10: Extracts the last digit of number.

+: Adds the last digit to the result of the recursive call.

4. Taking User Input

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

input("Enter a number: "): Prompts the user to enter a number.

int(): Converts the input (string) into an integer.

number: Stores the user-provided number.

5. Handling Negative Input

result = sum_of_digits(abs(number))

abs(number): Converts the number to its absolute value (removes any negative sign).

This ensures the function works correctly for negative numbers.

result: Stores the result of the function call.

6. Displaying the Result

print(f"The sum of the digits of {number} is {result}.")

print(f"..."): Displays the sum of the digits in a user-friendly format using an f-string.

The original number and its sum are dynamically inserted into the string.

#source code --> clcoding.com