Python: Reverse the digits of a given number and add it to the original

Last update on December 21 2024 07:19:20 (UTC/GMT +8 hours)

Palindrome Sum Iteration

Write a Python program to reverse the digits of a given number and add them to the original. Repeat this procedure if the sum is not a palindrome.

Note: A palindrome is a word, number, or other sequence of characters which reads the same backward as forward, such as madam or racecar.

Visual Presentation:

Sample Solution:

Python Code:

# Function to reverse a number and add it to the original number until a palindrome is obtained
def rev_number(n):
    s = 0  # Initialize a variable to count the number of iterations
    while True:
        k = str(n)  # Convert the number to a string for comparison
        if k == k[::-1]:  # Check if the number is a palindrome
            break  # If it is a palindrome, exit the loop
        else:
            m = int(k[::-1])  # Reverse the digits and convert back to an integer
            n += m  # Add the reversed number to the original number
            s += 1  # Increment the iteration count
    return n  # Return the palindrome obtained

# Test cases
print(rev_number(1234))  # Example: 1234 + 4321 = 5555 (palindrome)
print(rev_number(1473))  # Example: 1473 + 3741 = 5214 + 4125 = 9339 (palindrome)

Sample Output:

5555
9339

Explanation:

Here is the breakdown of the above Python exercise:

• Function Definition: The function "rev_number()" takes an integer 'n' as input.
• Initialization: Initializes a variable 's' to count the number of iterations.
• Palindrome Check and Transformation:
• Enters a loop that continues until the number 'n' becomes a palindrome.
• Converts the current number 'n' to a string 'k'.
• Checks if 'k' is equal to its reverse (k[::-1]), indicating a palindrome.
• If not a palindrome, reverse the digits of n (m) and adds it to 'n'.
• Increments in the iteration count 's'.
• Return Palindrome: Returns the final palindrome obtained.
• Test Cases:
• Calls the rev_number function with different initial numbers to demonstrate the transformation into palindromes.
• Example: rev_number(1234) results in 5555 because 1234 + 4321 = 5555, which is a palindrome.
• Example: rev_number(1473) results in 9339 after multiple iterations, forming a palindrome.

Flowchart:

Python Code Editor:

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