Chapter 5, Problem 18C

Recursive method for palindrome:

The recursive method for palindrome is given below:

Create the method palindrome() that accepts the input parameter as “s”, “low”, and “high” to check the low index of string is equal to high index of string and recursively call palindrome() method by passing the parameters of “s”, “low+1”, and “high-1” to check the string is palindromes or not.

//Define the palindrome() method

public static boolean palindrome(String s, int low, int high)

{

  //Check whether "low" is less than "high"

  if(low < high)

  {

/*Check whether first index of string and last index of string is equal and then call palindrome() method recursively. */

if (s.charAt(low)==s.charAt(high-1) && palindrome(s, low + 1, high-1))

  //Return true, string is palindrome

  return true;

/*Otherwise, return false that the string is not palindrome. */

  else

  return false;

  }

/*Otherwise, return true that the string is palindrome. */

  else

  //Assume in this case, low == high

  return true;

}

Explanation:

In the above code,

• It accepts the input parameter as “s”, “low”, and “high”.
• Check whether the “low” is less than “high”. If yes,
  • Check whether the index of “low” string is equal to index of “high-1” string and Call palindrome() method by passing the parameters as “s”, “low+1”, and “high-1” recursively. If yes,
    • Return true that the given string is palindrome.
  • Otherwise, return false that the given string is not palindrome...