Recursive program to check if number is palindrome or not
Given a number, the task is to write a recursive function which checks if the given number is palindrome or not.
Examples:
Input : 121 Output : yes Input : 532 Output : no
The approach for writing the function is to call the function recursively till the number is completely traversed from the back. Use a temp variable to store the reverse of the number according to the formula which has been obtained in this post. Pass the temp variable in the parameter and once the base case of n==0 is achieved, return temp which stores the reverse of a number.
Below is the implementation of the above approach:
C++
// Recursive C++ program to check if the // number is palindrome or not #include <bits/stdc++.h> using namespace std; // recursive function that returns the reverse of digits int rev(int n, int temp) { // base case if (n == 0) return temp; // stores the reverse of a number temp = (temp * 10) + (n % 10); return rev(n / 10, temp); } // Driver Code int main() { int n = 121; int temp = rev(n, 0); if (temp == n) cout << "yes" << endl; else cout << "no" << endl; return 0; } |
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Java
// Recursive Java program to // check if the number is // palindrome or not import java.io.*; class GFG { // recursive function that // returns the reverse of digits static int rev(int n, int temp) { // base case if (n == 0) return temp; // stores the reverse // of a number temp = (temp * 10) + (n % 10); return rev(n / 10, temp); } // Driver Code public static void main (String[] args) { int n = 121; int temp = rev(n, 0); if (temp == n) System.out.println("yes"); else System.out.println("no" ); } } // This code is contributed by anuj_67. |
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Python3
# Recursive Python3 program to check # if the number is palindrome or not # Recursive function that returns # the reverse of digits def rev(n, temp): # base case if (n == 0): return temp; # stores the reverse of a number temp = (temp * 10) + (n % 10); return rev(n / 10, temp); # Driver Code n = 121; temp = rev(n, 0); if (temp != n): print("yes"); else: print("no"); # This code is contributed # by mits |
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C#
// Recursive C# program to // check if the number is // palindrome or not using System; class GFG { // recursive function // that returns the // reverse of digits static int rev(int n, int temp) { // base case if (n == 0) return temp; // stores the reverse // of a number temp = (temp * 10) + (n % 10); return rev(n / 10, temp); } // Driver Code public static void Main () { int n = 121; int temp = rev(n, 0); if (temp == n) Console.WriteLine("yes"); else Console.WriteLine("no" ); } } // This code is contributed // by anuj_67. |
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PHP
<?php // Recursive PHP program to check // if the number is palindrome or not // Recursive function that returns // the reverse of digits function rev($n, $temp) { // base case if ($n == 0) return $temp; // stores the reverse of a number $temp = ($temp * 10) + ($n % 10); return rev($n / 10, $temp); } // Driver Code $n = 121; $temp = rev($n, 0); if ($temp != $n) echo "yes"; else echo "no"; // This code is contributed // by Sach_Code ?> |
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Output:
yes
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