Reverse and Add Function

The reverse and add function starts with a number, reverses its digits, and adds the reverse to the original. If the sum is not a palindrome, repeat this procedure until it does.

Write a program that takes number and gives the resulting palindrome (if one exists). If it took more than 1,000 iterations (additions) or yield a palindrome that is greater than 4,294,967,295, assume that no palindrome exist for the given number.

Examples:

Input : 195
Output : 9339

Input : 265
Output: 45254

Input : 196
Output : No palindrome exist

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

C++

// C++ Program to implement reverse and add function 
#include<bits/stdc++.h> 
using namespace std; 
  
/* Iterative function to reverse digits of num*/
long long reversDigits(long long num) 
{ 
    long long rev_num = 0; 
    while (num > 0) 
    { 
        rev_num = rev_num*10 + num%10; 
        num = num/10; 
    } 
    return rev_num; 
} 
  
/* Function to check whether he number is palindrome or not */
bool isPalindrome(long long num) 
{ 
    return (reversDigits(num) == num); 
} 
  
/* Reverse and Add Function */
void ReverseandAdd(long long num) 
{ 
    long long rev_num=0; 
    while (num <= 4294967295) 
    { 
        // Reversing the digits of the number 
        rev_num = reversDigits(num); 
  
        // Adding the reversed number with the original 
        num = num + rev_num; 
  
        // Checking whether the number is palindrome or not 
        if (isPalindrome(num)) 
        { 
            printf("%lld\n",num); 
            break; 
        } 
        else if (num > 4294967295) 
        { 
            printf("No palindrome exist"); 
        } 
    } 
} 
  
// Driver Program 
int main() 
{ 
    ReverseandAdd(195); 
    ReverseandAdd(265); 
    return 0; 
} 

Java

// Java Program to implement reverse and add function 
public class ReverseAdd  
{ 
    /* Iterative function to reverse digits of num*/
    long reversDigits(long num) 
    { 
        long rev_num = 0; 
        while (num > 0) 
        { 
            rev_num = rev_num*10 + num%10; 
            num = num/10; 
        } 
        return rev_num; 
    } 
  
    /* Function to check whether he number is 
           palindrome or not */
    boolean isPalindrome(long num) 
    { 
        return (reversDigits(num) == num); 
    } 
  
    /* Reverse and Add Function */
    void ReverseandAdd(long num) 
    { 
        long rev_num = 0; 
        while (num <= 4294967295l) 
        { 
            // Reversing the digits of the number 
            rev_num = reversDigits(num); 
  
            // Adding the reversed number with the original 
            num = num + rev_num; 
  
            // Checking whether the number is palindrome or not 
            if(isPalindrome(num)) 
            { 
                System.out.println(num); 
                break; 
            } 
            else if (num > 4294967295l) 
            { 
                System.out.println("No palindrome exist"); 
            } 
        } 
    } 
      
    // Main method 
    public static void main(String[] args)  
    { 
        ReverseAdd ob = new ReverseAdd(); 
        ob.ReverseandAdd(195l); 
        ob.ReverseandAdd(265l); 
          
    } 
} 

Python

#Python Program to implement reverse and add function 
  
# Iterative function to reverse digits of num 
def reversDigits(num): 
    rev_num=0
    while (num > 0): 
        rev_num = rev_num*10 + num%10
        num = num/10
    return rev_num 
  
# Function to check whether the number is palindrome or not 
def isPalindrome(num): 
    return (reversDigits(num) == num) 
  
# Reverse and Add Function 
def ReverseandAdd(num): 
    rev_num = 0
    while (num <= 4294967295): 
        # Reversing the digits of the number 
        rev_num = reversDigits(num) 
  
        # Adding the reversed number with the original 
        num = num + rev_num 
  
        # Checking whether the number is palindrome or not 
        if(isPalindrome(num)): 
            print num 
            break
        else: 
            if (num > 4294967295): 
                print "No palindrome exist"
  
# Driver Code 
ReverseandAdd(195) 
ReverseandAdd(265) 

C#

// C# Program to implement reverse and add function 
using System; 
  
class GFG  
{ 
    /* Iterative function to reverse digits of num*/
    static long reversDigits(long num) 
    { 
        long rev_num = 0; 
        while (num > 0) 
        { 
            rev_num = rev_num * 10 + num % 10; 
            num = num / 10; 
        } 
        return rev_num; 
    } 
  
    /* Function to check whether he number is 
        palindrome or not */
    static bool isPalindrome(long num) 
    { 
        return (reversDigits(num) == num); 
    } 
  
    /* Reverse and Add Function */
    static void ReverseandAdd(long num) 
    { 
        long rev_num = 0; 
        while (num <= 4294967295) 
        { 
            // Reversing the digits of the number 
            rev_num = reversDigits(num); 
  
            // Adding the reversed number with the original 
            num = num + rev_num; 
  
            // Checking whether the number is palindrome or not 
            if(isPalindrome(num)) 
            { 
                Console.WriteLine(num); 
                break; 
            } 
            else if (num > 4294967295) 
            { 
                Console.WriteLine("No palindrome exist"); 
            } 
        } 
    } 
      
    // Driver code 
    public static void Main()  
    { 
        ReverseandAdd(195); 
        ReverseandAdd(265); 
    } 
} 
  
// This code is contributed by chandan_jnu 

PHP

<?php 
// PHP Program to implement reverse and add function 
  
/* Iterative function to reverse digits of num*/
function reversDigits($num) 
{ 
    $rev_num = 0; 
    while ($num > 0) 
    { 
        $rev_num = $rev_num * 10 + $num % 10; 
        $num = (int)($num / 10); 
    } 
    return $rev_num; 
} 
  
/* Function to check whether he number 
   is palindrome or not */
function isPalindrome($num) 
{ 
    return (reversDigits($num) == $num); 
} 
  
/* Reverse and Add Function */
function ReverseandAdd($num) 
{ 
     $rev_num = 0; 
    while ($num <= 4294967295) 
    { 
        // Reversing the digits of the number 
        $rev_num = reversDigits($num); 
  
        // Adding the reversed number with 
        // the original 
        $num = $num + $rev_num; 
  
        // Checking whether the number is 
        // palindrome or not 
        if (isPalindrome($num)) 
        { 
            print($num . "\n"); 
            break; 
        } 
        else if ($num > 4294967295) 
        { 
            print("No palindrome exist"); 
        } 
    } 
} 
  
// Driver Code 
ReverseandAdd(195); 
ReverseandAdd(265); 
  
// This code is contributed by chandan_jnu 
?> 

Output:

9339
45254

References: https://app.assembla.com/spaces/AASU_Fall2008_ProgrammingTeam/wiki

This article is contributed by Rahul Agrawal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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Recommended: Please try your approach on {IDE} first, before moving on to the solution.

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