Question

Write a recursive method to determine if a String is a palindrome.

The program should contain a String array that you can load several test cases to test your palindrome testing method.

The program should load your String Array with the test data containing the possible palindromes from a text file.

The program should test you application with a text file contained in your project folder

After testing your program with your test cases in the text file, you program should allow the user to test your program independently and interactively using Command Line Interface (CLI).

*******The code must commented properly**********

**********  You must permit the user to enter their own palindrome after the test in run******************

JavaIntelliJ

Answer 1

Here i am providing the answer. Hope it helps. please give me a like. it helps me a lot. If any queries please do comment. i will be happy in clarifying.

Java code for above problem

import java.util.*;
import java.io.*;
class Main
{
   // tetsing main method
   public static void main(String args[]) throws IOException
   {
       // this following steps prints results of strings.txt file
       Scanner input=new Scanner(new File("strings.txt"));
       while(input.hasNext())
       {  
           String str=input.nextLine();
           System.out.println(isPalindrome(str));
       }
      
       // the following lines of codes takes input from user from command line and prints the result
       input=new Scanner(System.in);
       System.out.print("\nEnter a string: ");
       String str=input.nextLine();
       System.out.println(isPalindrome(str));
   }
  
   // method that returns the string saying the given string is palindrome or not
   public static String isPalindrome(String str)
   {
       if(isPalin(str,0,str.length()-1))
           return "\""+str+"\" is a palindrome";
       return "\""+str+"\" is not a palindrome";
   }
  
   // recursive method that says whether the given string is palindrome or not
   public static boolean isPalin(String str,int start,int end)
   {
       if(start>=end)
           return true;
       if(str.charAt(start)!=str.charAt(end))
           return false;
       return isPalin(str,start+1,end-1);
   }
}

Sample output

if "strings.txt" has following data

abcd
aaa
madam
string
radar
holidays
enjoy

then after running the above code, output looks as follows:

Thank you. please upvote.