Question

A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward as forward, such as madam or racecar. Write a recursive method in java that accepts a integer as its argument and returns true if it is palindrome, false otherwise.

public class Recursion {

                public static void main(String[] args) {

                                Recursion r = new Recursion();

                                System.out.println(“Is 12321 a palindrome? “+ra.isPalindrome(12321)); //true

                }

                public Boolean isPalindrome(int num){

                                return false;

                }

}

Answer 1

public class Recursion {
  public static void main(String[] args) {
    Recursion r = new Recursion();
    System.out.println("Is 12321 a palindrome? "+r.isPalindrome(12321)); //true
  }

  public Boolean isPalindrome(int num){
    return num == rev(num,0);
  }

  int rev(int n, int temp) {
    if (n == 0)
      return temp;

    temp = (temp * 10) + (n % 10);
    return rev(n / 10, temp);
  }
}

Is 12321 a palindrome? true